2000–2005

Roush Racing announced during the 2000 season that Busch was being promoted to the Winston Cup Series to replace Chad Little in Roush's No. 97 Ford for the 2001 season. Little ended up being released early, and Busch took over the No. 97 John Deere-sponsored Ford at Dover in September 2000. Busch ran seven of the final eight races (Little drove at Talladega) with crew chief Jeff Hammond. Busch's best finish was a 13th-place finish at Charlotte.

Busch began the 2001 season driving an unsponsored car after John Deere pulled out of sponsoring the 97 following the 2000 season. Roush would eventually sign Rubbermaid to a multi-year sponsorship contract later in the year, with its Sharpie marker brand carried as Busch's primary sponsor. scored three Top 5's and six Top 10's that year. During the 2001 Daytona 500, he and Dale Earnhardt made door-to-door contact on lap 85, and Earnhardt responded by giving Busch the finger out of his driver's side window at 185 mph;^[8] the Fox Sports replay cameras caught this, leading broadcaster Mike Joy to remark "Kurt, you're number one." To this day, Busch recalls this as the only time he encountered Earnhardt, who was killed in a crash on the last lap of that race, on the track. Busch was the last remaining driver to compete against Earnhardt in a Cup race when he retired.

Busch scored his best finish of third at the spring Talladega race, which was three weeks after scoring his first career Top 5 finish at Texas (fourth), and he added a fifth-place in the Brickyard 400 at Indianapolis. He also had some unlucky breaks over the course of the year, especially in the second half where he crashed out of the Southern 500 at Darlington, where he led 74 laps; at Martinsville, where he let 38 laps before cutting a tire in heavy traffic, which ended up causing significant damage to the race car; at Rockingham, where he battled overheating issues despite leading 45 laps; and in the penultimate race at Atlanta, where he failed to qualify. He closed the season with a 21st-place finish at the postponed event at New Hampshire, finishing 27th in points and second behind Kevin Harvick for Cup rookie of the year.

The 2002 season was Busch's breakout year in the Winston Cup Series. He claimed his first victory in the Food City 500 at Bristol, after battling hard with rival Jimmy Spencer on worn tires. Busch added a second win at Martinsville in October and then won at Atlanta the next week and in the season finale at Homestead. This gave Busch four wins, 12 Top 5's, 20 Top 10's, and one pole, all of which would allow him to finish third in the final standings for the year. He finished the season particularly strong, winning three of the final five races and finishing third and sixth, and leading many laps in the next two. As well as his finish in the point standings, he also collected $5,105,394. The 2002 season saw Kurt Busch become the first driver in NASCAR history to win the most races in his first-ever winning season with four. He is one of only two drivers to accomplish this feat, along with Carl Edwards, who did it three years later in 2005.

Busch had an "up and down" year in 2003. He once again recorded four wins, including a season sweep at Bristol, making him the first driver to do that since Rusty Wallace accomplished the feat in 2000). However, inconsistent results later in the season resulted in Busch falling out of the Top 10 in points; he finished in 11th place with nine Top 5's and 14 Top 10's, although he collected over US$5,000,000 again that year. Busch was also involved in a bit of NASCAR history during the Carolina Dodge Dealers 400, held at Darlington on March 16 of that year. In the closing laps of the race, he and Ricky Craven were engaged in a tight battle for the lead. Both drivers battled loose race cars as well as each other to the finish. Busch held the lead heading into the final corner but Craven managed to pull almost even exiting turn four. With the finish line approaching both cars made contact and bumped each other repeatedly headed to the checkered flag. When it dropped, Craven had crossed the line .002 seconds before Busch and scored the victory in what was the closest ever finish to a race in NASCAR history.

In 2004, Busch won three races, two poles, and the inaugural NASCAR Nextel Cup Championship, the first year NASCAR held "The Chase for the Championship". He won his fourth consecutive race at Bristol after winning the Food City 500 in March (winning that race for the third consecutive year), and became the second driver to win both races at New Hampshire Motor Speedway in a single season. At Homestead for the final race of the season, Busch nearly lost the championship. On lap 93, Busch entered the access road in turns 3 and 4 that leads to pit road telling his crew that he has a flat right front tire. As Busch came off the access road and was about to enter the pits, the right front wheel, the same one he told his crew was flat even though it wasn't, came off the car. As the wheel came off his car, Kurt darted left and almost hit the yellow barrels on the entrance of pit road. If Busch hit those barrels, his championship would have been lost. The caution came out as the tire rolled down the entire front stretch. Busch fell to third in the standings but was able to get his positions back and won the championship. He scored 10 Top 5's and 21 Top 10's.

In 2005, midway through the season, Busch announced that he would be leaving Roush Racing at the end of the season and would replace Rusty Wallace in the No. 2 Miller Lite-sponsored Dodge for Penske Racing South. Initially, Roush was unhappy with Busch's decision to leave his team but when Chip Ganassi Racing announced that Jamie McMurray wanted to join Roush Racing in 2006, Roush agreed to let Busch go.

Busch won three races during the 2005 season, along with nine Top 5's and 18 Top 10's in 34 races. He also scored an average finish of 15.3. Which all allowed him to finish 10th in the final points standings.

2006–2010

Busch was released from Roush Racing at the end of 2005^[9] and joined Penske Racing South in 2006. Busch had asked team owner Jack Roush to let him out of his contract at the end of 2005, but Roush initially refused. However, after Chip Ganassi released Jamie McMurray from his 2006 contract, Roush decided to release Busch when Roush learned that Busch already signed a contract with Roger Penske before the season ended. Busch's last race with Roush-Fenway Racing and 2005 was at Texas before the final two races; because he was parked by NASCAR for an incident with the police (see below). Busch appealed and a misunderstanding on the police's part was cleared before the races but the parking penalty was held in place.^{[citation needed]}

McMurray, who was originally slated to join Roush in 2007 to drive the No. 6 (which ultimately went to David Ragan), instead replaced Busch in the No. 97, which was then renumbered to No. 26.

In the 2006 season, driving for Penske, Busch scored one win at Bristol Motor Speedway in the Food City 500, his fifth win at the track. Busch celebrated the victory by getting out of his car and making a snow angel on the track, due to snow that had fallen at the track that weekend. He also won six poles and had seven Top 5's and 12 Top 10 finishes but finished 16th in the final standings. He also made his Busch Series debut for Penske in the No. 39 Dodge at Texas Motor Speedway, winning in his first race. He ran six more races that season and picked up a second win at Watkins Glen International by holding off Robby Gordon on the final lap. Gordon and Busch on the final lap struggled for the win but it resulted in Busch holding onto the lead in the outer-loop to seal up the win. In victory circle, Busch thanked Gordon for a fight for victory and said that the struggle reminded him of his 2003 Carolina Dodge Dealers 400 at Darlington when Ricky Craven beat Busch by one inch to win the race after a 2 lap-long struggle to the checkers. Kurt would miss the chase for the first time in 2006 and finished 16th in the points standings.

In the 2007 season, Busch had two wins, one pole, scored five Top 5's, and 10 Top 10's through 26 races, and qualified for the Chase for the Sprint Cup. Busch's on-track performance increased noticeably after the addition of Pat Tryson as his crew chief midway through the season.^[10] He also ran four more Busch races, earning 2 top-five and 3 top-ten finishes.

In 2008, to make sure rookie teammate Sam Hornish Jr. would be guaranteed a starting spot in the season's first five races, the owner's points from Busch's No. 2 car were transferred over to the No. 77 car driven by Hornish. Busch would still be guaranteed a starting spot, due to NASCAR's Champion's Provisional Rule, which states that the most recent series champion not in the Top 35 in the previous season's final owner points automatically qualifies for a race. (With his 2004 championship, Busch was by several years the most recent).

At the 2008 Daytona 500, Busch was contending to win and had a fast car on the final lap capable to win. He and his teammate Ryan Newman got by Joe Gibbs Racing rivals, Tony Stewart and Kurt's brother Kyle on the final lap, and Kurt decided to instead of trying for the win himself, push Newman to victory. In turn 4 Newman cleared further challenges and won the race, thanking his win on Busch in the victory circle. It was Roger Penske's first Daytona 500 win and it made Penske one of the few owners to win both the Indianapolis 500 and Daytona 500 in an owner career.

On June 29, 2008, Busch broke a 29-race winless streak at New Hampshire Motor Speedway when the Lenox Industrial Tools 301 was called due to rain on lap 284. It was his first win since Michigan's late summer race in 2007, and his fourth win since joining Penske Racing and 18th overall. Kurt would miss the chase again in 2008 and finished 18th in the points standings.

He began his 2009 season at the 2009 Daytona 500, he was involved in a wreck on lap 124 when Dale Earnhardt Jr. swerved into Brian Vickers. Vickers shot up the track and hit the wall, ricocheting into Denny Hamlin, who came down into Busch. He then spun into the grass along with eight other drivers including his brother Kyle. Busch made numerous pit stops to repair the car and was able to finish tenth. Kurt was one of the many that believed Dale Jr.'s contact was intentional and Kurt joined Earnhardt's fans, the drivers, and owners in calling NASCAR to penalize Earnhardt, for the rest of the race but this was not granted.

Busch then qualified fourth for the season's second race at the Auto Club Speedway in Fontana, California. He ran in the top five most of the race and finished fifth. This moved him up seven spots in the standings to third. Busch led most of the race the 2009 Kobalt Tools 500, leading 235 of 325 laps and getting his nineteenth Sprint Cup Series victory. He led more laps in the race than he did in the entire 2008 season. At Las Vegas, he and his younger brother Kyle had a touching moment when Kyle Busch won at Las Vegas, their hometown. In the victory circle, Kurt came in and shared a big hug with Kyle. Legendary driver and NASCAR announcer Darrell Waltrip called it "The most touching thing I have ever seen."^[11]

He remained in the Top 5 in points for the rest of the season. He qualified for the Chase and ended up fourth in the standings, the highest-ranked car that was not under the Hendrick Motorsports banner. Busch picked up another win at the 2009 Dickies 500 after his brother Kyle ran out of fuel with two laps to go.

For the 2010 season, Penske Racing brought rookie, Brad Keselowski on board to drive the No. 12 Penske Racing Dodge Charger. Busch and Sam Hornish would be his teammates. Keselowski also ran a full-time Nationwide Series, driving the No. 22 Dodge Challenger. 2009 Rookie Justin Allgaier accompanied him in the Nationwide Series. Steve Addington, who was Kyle Busch's crew chief for the past two seasons and led the younger Busch to 14 victories, became the crew chief for Kurt at the start of the 2010 season, as Pat Tryson left to join Michael Waltrip Racing as Martin Truex Jr.'s crew chief.

On May 22, 2010, Busch won the 26th Annual NASCAR Sprint All-Star Race. He then followed it up by winning the Coca-Cola 600 the following weekend, becoming only the seventh driver to win both in the same year. Busch eventually made the Chase being seeded fifth in points. Busch also, amazingly, finished seventh at Daytona at the Coke Zero 400 after wrecking three times in the last 12 laps.

Busch would finish out the season 11th among the Chase contenders.

2011: #22 car and final season at Penske

In 2011, Busch and Keselowski swapped teams and crews. Busch took over a renumbered No. 22 Dodge. Busch earned his first Budweiser Shootout win after Denny Hamlin went below the yellow line at the end of the race at Daytona. He would go on to win the 2011 Gatorade Duel 1, and because of polesitter Dale Earnhardt Jr.'s crash in practice, which forced him into a backup car, Busch started in first for the 2011 Daytona 500 and started the 2011 season three for three.

During the Crown Royal 400 at Richmond International Raceway, Busch went on a profanity-laced tirade on his in-car radio that appeared to be directed at then Penske technical director Tom German.^[12]

Busch won the pole for and led most of the race at Kansas, for 152 laps. However, a fuel pickup issue late hurt his chances of winning. Teammate Brad Keselowski took the victory. However, a few weeks later on June 26, Kurt finally got an elusive road course victory at Infineon Raceway. Not only did he win, but he also led the most laps with 76. Because of Brad Keselowski's injury during a practice crash at Road Atlanta, Busch filled in for Keselowski in his NASCAR Nationwide Series car for the Zippo 200 at Watkins Glen International, and Busch managed to get the pole and the win. By August 13, 2011, Busch had won 1/4 of all of his Nationwide races. On October 2, Busch won on two late restarts beating Jimmie Johnson in turn 1 leading the final 43 laps to grab his first-ever victory at the Monster Mile at Dover which would end up being his final victory for Penske. After a frustrating final five races, things came to a head when Busch launched a verbal tirade against an ESPN cameraman and gave an obscene gesture to workers when a car blocked his path towards his pit garage following a transmission failure at the same race.^[13] Crew chief Steve Addington moved to Stewart-Haas Racing after the 2011 season.

First media incidents and release

In the post-race interview of the fall Richmond race, Busch was quoted as saying on ABC that he was "in [Johnson's] head,".^[14] He had to be restrained after the race when NASCAR.com reporter Joe Menzer asked "Kurt, can either you or Jimmie win the Chase...". Busch cut Menzer off replying "How did I see you were going to come with that? We’re good." and started to walk away. Busch ultimately shouted expletives and physically went after Menzer before Penske team members had to physically restrain him.^[14] AP journalist Jenna Fryer later in a press conference asked Johnson about the comment during the ABC post-race interview, Busch interrupted saying "I didn't say that tonight. Did not." Fryer offered to show him the ABC transcript, which he looked at after the interview. Busch proceeded to tear up the transcript showing he had made these statements and walked out of the media center.^[14] Busch would apologize to Menzer and Fryer afterward.^[14]

At the start of the Sylvania 300 at New Hampshire Motor Speedway, Busch's team was delayed in rolling their car to pit road until after the national anthemdue to issue with pre-race car inspection; the rear-end housing being outside of its allowable tolerances. ESPN reporter Jamie Little, walking with Busch, asked if he was OK with her asking a question. Busch responded, "Why the fuck do you think I would be OK? I gotta go get in my car. NASCAR told me I gotta get in my car."^[15]

In the final race of the 2011 season, Busch's transmission failed on the third lap of the race. While his car was undergoing repairs, Busch verbally abused Dr. Jerry Punch while waiting to be interviewed by Punch for ESPN, in an incident captured by a fan and posted on YouTube.^[16] NASCAR fined Busch $50,000 for his actions during the race, and Penske Racing issued an apology for Busch's "inappropriate actions".^[17] During Championship week ceremonies, Busch said that he had been working with a sports psychologist for two months, to work on "personal issues", acknowledging "I need to be a better person on the radio, to the team, as a leader. It's personal issues, of course, and working with a sports psychologist, I've gotten obviously a small grasp, but there are obviously bigger things that I need to accomplish and things can't happen overnight".^[18]

Busch's employment with Penske Racing was terminated on December 5, 2011. Although most observers of the sport believe he was fired,^[19] both sides stated that the parting was mutual.^[20] In contrast, the Charlotte Observer reported several sources confirming team owner Roger Penske decided that Busch's altercation at Homestead-Miami Speedway was the last straw in his stormy tenure with the team but chose to defer the announcement until after Champion's Week.^[21] He was replaced in the No. 22 by A. J. Allmendinger.

2012: First winless season

Following his release from Penske Racing, Busch realized that he wasn't "having fun" anymore and, next to going to therapy for his anger problems, wanted to "put the fun back into racing." As a result, Busch declined an offer from Richard Petty Motorsports in favor of an early-season agreement to drive for Phoenix Racing, in the No. 51 Chevrolet, for the 2012 Sprint Cup Series season.^[22] He also talked to Michael Waltrip Racing, Furniture Row Racing and Richard Childress Racing to see if any rides were available at those teams.^[4] He also ran a limited Nationwide Series schedule for the team.^[23] At the same time, Busch formed a sponsorship relationship with Monster Energy Drink in which he signed a deal with Kyle Busch Motorsports, to share the No. 54 car with his younger brother in the Nationwide Series.^[24]

At the 2012 Aaron's 499 at Talladega, Busch paid homage to the 2006 racing comedy Talladega Nights: The Ballad of Ricky Bobby by running his No. 51 car with the paint scheme of Ricky Bobby's No. 62 "ME" Cougar car from the movie, causing NASCAR on Fox commentators Mike Joy, Larry McReynolds and Darrell Waltrip to jokingly refer to Busch as "Ricky Bobby" throughout the race, and Busch also dropped movie lines into radio chatter with his spotter and crew chief. Busch's girlfriend Patricia Driscoll spent months getting permission from Sony and Will Ferrell as well as other trademark and license holders. Busch's real-life fall from grace during the 2011–12 Sprint Cup offseason has been compared to Ricky Bobby's.^[25] Busch's car was one of the stronger performers, running near the front and leading for a few laps. Towards the end of the race, with six laps to go, he dropped back when he spun out in the trioval off ex-teammate Brad Keselowski's bumper. After stopping, Busch drove backward down pit road to get replacement tires, though he was not penalized and finished in 20th place as the last car on the lead lap.

At Darlington, Busch was turned with Ryan Newman, and both drivers' days were ended. Busch was fined $50,000 and put on a five-race probation and Newman was not penalized. Busch would finish the race in 21st, the last car on the lead lap.

On June 4, 2012, Busch feuded with Justin Allgaier at the Nationwide event at Dover and after talking to his boss and brother Kyle. When asked by Bob Pockrass about being on probation, Busch said, "It refrains me from not beating the shit out of you right now because you ask me stupid questions. But since I'm on probation, I suppose that's improper to say as well. If you can talk about racing things, we'll talk about many things, Bob. It is not racing, you're here just to start stuff, you know that's you're all out here for!" NASCAR immediately suspended Busch from the Pocono race as a result of violating their policy forbidding swearing publicly.^[26]

The following week NASCAR suspended Busch until June 13, 2012, and extended his probation until December 31. Busch was already on probation for the confrontation with Newman and his crew following the May 12, 2012, Sprint Cup race at Darlington and for driving recklessly through Newman's pit stall.

According to a NASCAR news release, Busch was suspended for violating Section 12-1 of the NASCAR rulebook, which covers "actions detrimental to stock car racing; violation of probation; verbal abuse to a media member."^{[citation needed]}

On July 6, 2012, Busch won the Nationwide Series Jalapeño 250 at Daytona by passing Austin Dillon on the final lap.

During his 7–8-month stint with James Finch, he finished third at Sonoma after leading a few laps and running in the top three all race long. However, his nearest miss took place at Talladega that autumn. There Busch controlled the race early and mid-way and spun out from contact with Jamie McMurray. He was parked by NASCAR after driving away from the safety officials who were trying to assist him and he would not stop his car even though NASCAR was telling him to do so. The following week he began driving for Furniture Row Racing. Kurt would miss the Chase for the first time since 2008 and finished a dismal 25th in the points standings.

2012

On September 24, 2012, it was announced that Busch would drive the No. 78 Chevrolet SS for Furniture Row Racing for the 2013 season, replacing Regan Smith.^[27] The connection started when then-crew chief Todd Berrier called Busch to gauge his interest in driving for FRR.^[4]

In his first start for FRR at the 2012 Bank of America 500, Busch finished 21st. He had a 25th-place finish the following week at Kansas. Busch later rebounded with three consecutive Top 10 finishes at Texas, Phoenix, and Homestead to end the season.

2013: Return to The Chase

2013 started for Busch the very same way that 2012 had – driving with a new team, in this case, Furniture Row Racing. Despite this, Busch showed off significant improvement over the off-year that had been 2012, both for himself and FRR as a whole: in the three years the car was driven by Regan Smith, Furniture Row Racing had only one win, three top-five, and six top-ten finishes, and only led 42 laps in Sprint Cup competition. In comparison, in the first 23 races of 2013, Busch had five top-five finishes, nine top-ten finishes, one pole, and had led 270 laps, more than six times as many laps as the car had ever led with Smith in the previous three seasons.

Busch started the 2013 season crashing in the Sprint Unlimited on lap 14, finishing in 13th place. He finished fifth in the Budweiser Duel, but poor handling made him finish the Daytona 500 in 28th place, five laps down. He did not improve much the next week at Phoenix, where he finished one lap down in twenty-seventh place. He then had a twentieth-place finish at Las Vegas. After three less successful runs, he hit a resurgence, getting a fourth-place finish at Bristol.

At Fontana, Busch went a lap down briefly after being penalized for speeding during green-flag pit stops, but he surged back in the last laps to finish in third place behind his brother Kyle Busch and Dale Earnhardt Jr.

At Martinsville, Busch had bad luck. He crashed early in the race and after repairing his damages, successfully took the lucky dog free pass. But later, on lap 487, while running many laps down, Busch lost his brakes in turn 1 and slammed the wall hard enough to cause his engine to burst into flames. This brought out a 6-minute red flag. Busch was uninjured.

At Texas, Busch almost acquired the pole position with a qualifying speed of 195.688 mph, but the final one to qualify; his younger brother managed to win the pole with a speed of 196.299 mph to conclude qualifying. Busch ended up starting second, but still on the front row. However, he was disappointed to lose the pole, saying "I would rather lose to Kyle than anybody else... it is frustrating that I do lose it to him though."

At Richmond, Busch led for 36 laps and contended for victory. However, on a final restart, he again tangled with Tony Stewart. He had bumped Stewart on the restart causing Stewart to finish out of the top-ten. After the race ended the two cars exchanged shoves and the two argued on pit road, drawing attention away from the race winner Kevin Harvick. Both were summoned to the NASCAR hauler. Busch finished in ninth place and said to reporters that he did not intentionally hit Stewart and said he was surprised and disappointed when Stewart retaliated after the checkers.

At Talladega, Busch led two laps and was in the top-ten on lap 182 when he was collected in a large pileup on the back straightaway. He took the worst damage in the crash, as J. J. Yeley got loose from contact with Ricky Stenhouse Jr., went across the track, and hit him with enough force that Busch turned sideways, flipped over once, and landed on top of Ryan Newman, then slid off Newman and struck the outside wall, and was hit again by Clint Bowyer and Bobby Labonte. Busch was uninjured.

At Darlington, Busch won his first pole position of the year. From the drop of the green flag, Busch led 69 of the first 80 laps, but his handling went away after the first green flag pit stops and he was forced to settle for a fourteenth-place finish.

At the All-Star race, Busch started up front and led 29 laps, winning two of the four 20 lap segments, with brother Kyle winning the other two. However, a poor pit stop by both Busch brothers was responsible for causing them to lose the lead and race to Jimmie Johnson for the final ten-lap shootout. Kurt finished fifth.

At the Coca-Cola 600 a week later, Busch started second on the outside of the front row. Despite having to change a battery late in the race, he led eight laps and he still finished in third place, the first time he'd finished in the top three since June 2012 at Sonoma. When interviewed, he responded, "Yeah, a top-five is great. To be up front, to lead laps, that's what it's all about. So we'll get these little hiccups polished up and continue plugging forward. That's the only thing we can do, is learn from what exactly happened – was it a cable issue, a battery that was dead, was the alternator not charging? To show our strength tonight, to finish third, we'll take it. I think that's what needs to be said. The Furniture Row team was fast, and we didn't quite have a perfect night, and we brought it home third."^[28]

Busch then had a 12th-place finish at Dover and a seventh-place showing at Pocono. At Michigan, Busch qualified on the front row and led the first 21 laps, but went seven laps down when he got into an early accident on lap 30.

At Sonoma, Busch got his next top-five finish with a fourth-place finish, after leading fifteen laps, then battling back from a lap down after a pair of speeding penalties on pit road.

At Kentucky, brief controversy hit Busch as on lap 48, he was responsible for causing a seven-car wreck that was instigated when he went down on the apron, then came back up the track and turned Brad Keselowski approaching turn 1, causing Keselowski to shoot up the track and collect several more cars including Greg Biffle, Travis Kvapil and Dave Blaney. Busch finished sixth and followed this up with another sixth-place finish at the Coke Zero 400. This finish gave Furniture Row Racing their first-ever streak of three straight top-ten finishes, and also moved Busch up to ninth in the points. However the next week at Loudon, Busch started second and led 102 laps before he was turned and wrecked by Matt Kenseth and finished 31st.

At Indianapolis, Busch had a fourteenth place showing. The following week at Pocono, he led nine laps and recorded a third-place finish. This was followed by a ninth-place finish at Watkins Glen. Returning to Michigan, Busch started on the outside of the front row, led 43 laps, and finished third, bringing himself up to ninth in driver points.

At Bristol in August, Busch started on the outside row and led 54 laps early, before a loose wheel caused him to go behind the wall, resulting in a 31st-place finish, 26 laps down. However, he bounced back over the following two weeks, with a fourth-place finish at Atlanta. The following week at Richmond, Busch started second and had one of the strongest cars of the night, ultimately finishing second to Carl Edwards. This also marked Furniture Row Racing's first-ever appearance in the Chase.

At Chicagoland, Busch opened the Chase with a fourth-place finish. He then had a 13th-place finish at New Hampshire. At Dover, Busch finished 21st, three laps down, after he had to pit for a loose wheel. At Kansas, Busch was forced to start at the rear of the field when he crashed in practice and had to bring out a backup car. He managed to work his way through the field to finish second. This brought Busch up to ten top-five and fifteen top-ten finishes over 30 races. Busch would go on to finish tenth in the final standings.

Also in 2013, Busch planned to drive the No. 1 Chevrolet in the Nationwide Series for Phoenix Racing, competing in sixteen events; in the event he would run only three races during the season, wrecking at Daytona but having top-ten finishes at Talladega and the second race at Daytona.

2014: Return to Victory Lane

Busch had his outbreaking race for his new team at Fontana. He led a bit of the race after Jimmie Johnson blew a tire with 7 laps to go. He led on the restart against teammate Tony Stewart but lost the lead on the final lap after allowing Kyle Busch to slip past and win.

The next week at the STP 500, on lap 43, Busch collided with Brad Keselowski on pit road during a caution, causing massive damage to Keselowski's car. There would be several instances of beating and banging between the two drivers after Keselowski's car was repaired and came out of the garage. By the end of the race, Busch was battling Jimmie Johnson for the lead in the final 27 laps. Busch took the lead with 11 laps remaining, and kept it to win his first race since 2011, and first at Martinsville since 2002.^[31]

At Darlington, while running in the top five with 3 laps to go, Busch got tapped from behind by Clint Bowyer and spun out, hitting a barrier head-on. Because of energy-absorbing walls, Busch was uninjured, but waved angrily towards Bowyer under caution and showed discontent with Bowyer in post-race ceremonies. In regards to the incident with Bowyer, Busch said "That was a terrible way to end what could have been a decent night. We struggled at times to get the balance of the Haas Automation Chevrolet right, but we kind of found our spot just past the halfway point and made slight adjustments the rest of the way. We called for a two-tire stop at the end hoping to gain some track position, but it seemed like everyone had the same idea. We gained a little, but the guys behind us all had four tires. I tried to hold them off the best I could, but someone (Bowyer) moved me out of their way and it ruined our night. I hate it for the team, but we keep learning each week and we will get better."

At the Coca-Cola 600, Busch in his attempt to complete all 1,100 miles of the 2014 Indianapolis 500 and the Coca-Cola 600 in the same day, came up 194 miles short, blowing an engine on lap 274 after completing 271 of the 400 laps.

At Pocono, Busch qualified third. He led 5 laps throughout the race and ran in the top five all day long. He ultimately finished third; his best finish since his win at Martinsville.

At Daytona Busch qualified 42nd; despite this Busch led the most laps. However, he got passed by Aric Almirola on lap 111. 5 laps later a rain-shower soaked the speedway on lap 116 ending the race. In an interview, a disappointed Busch said "I didn't do my job. Third is good but I wanted to win." After the race, Busch was penalized 10 points and Daniel Knost was fined $10,000 for an illegal window automotive part accidentally installed before the race. Busch elected not to appeal the penalty.

After Daytona, Busch did much better. He had a top-five finish at Pocono and Watkins Glen. Daniel Knost parted ways with Kurt Busch mid-way into the Chase and Knost was replaced with Tony Gibson. Knost was given to Busch's teammate Danica Patrick. With Gibson as his new crew chief, Kurt did significantly better, qualifying his remaining races in the top ten. His best finish in a race during the Chase was seventh twice-at Talladega and Phoenix. During the NASCAR off-season, Busch had a widely publicized falling-out with his longtime girlfriend Patricia Driscoll, that led to acrimony and near-charges against Busch (see below).

2015

Busch started his season on a rough note in the 2015 Sprint Unlimited when he got collected in 2 multi-car accidents. At the second Budweiser Duel, he was running second behind Jimmie Johnson with nine laps to go. He went below the yellow line by accident and improved his spot. He was given a stop-and-go-penalty by officials which sent him to the back of the field for the final results.

On February 20, 2015, Busch was indefinitely suspended by NASCAR after a Delaware family court cited "more likely than not" that Busch had abused his ex-girlfriend Patricia Driscoll. The accusation came after the couple split up and she came to the Dover track and let herself into his motor coach without permission using Busch's entrance code. Regan Smith replaced him for the Daytona 500 along with the races held at Atlanta and Las Vegas.^[32] Kurt Busch applied for reinstatement ten days after the Daytona 500 and began his reinstatement program.

On March 11, 2015, NASCAR lifted Busch's indefinite suspension after prosecutors in Delaware determined there was not enough evidence to bring a criminal case against Busch, making him eligible to compete again, starting with the CampingWorld.com 500 at Phoenix. Driscoll is now under federal indictment for fraud and misusing charitable donations for personal gain. Additionally, Busch was granted a waiver by NASCAR, making him still eligible for the Chase if he won a race between then and the autumn Richmond event.^[33] In his first race back from suspension, Busch finished fifth. At Auto Club, Busch won the pole and led the most laps (65), before being bumped back to third due to a last-lap pass by Brad Keselowski and Kevin Harvick. The race ended in controversy as, according to an online poll, 69% of the fans suspected a fix in the waning laps on NASCAR's part. NASCAR denied the allegations but not before the controversy broke out for the next few days following the race.

The next week at Martinsville, Busch led early in the race. He faded to the tail end of the field mid-way. He briefly got penalized for moving lanes before the restart, but 20 laps later officials rescinded the penalty.

Busch later took the checkers after a dominating performance at Richmond. Battling Jamie McMurray for the win during the final 100 laps, Busch pulled away to win the race, his first win of the season.

Busch's second win came in a rain-shortened Michigan race.^[34] At Sonoma, Busch dominated early, before finishing second to younger brother Kyle in what was their first ever 1-2 finish in NASCAR Sprint Cup history.

Busch would finish 8th in 2015 championship points despite missing the first three races of the season, scoring 21 top 10s and 3 poles.

2016

Busch started the 2016 season bringing home a 10th-place finish in the Daytona 500 and winning two consecutive poles for Atlanta and Las Vegas. However, he was given the pole position for the former at Atlanta because his brother, Kyle Busch, earned that spot in qualifying but started dead-last after his time was disallowed due to failing post-qualifying inspection. He got his first and only victory of the season at Pocono, ironically the only race of the season when his crew chief Tony Gibson was suspended. Busch had a very consistent season, breaking a record for most consecutive lead-lap finishes to start the year. His streak ended, however, when he got his first DNF of the season during the 23rd race at Bristol after suffering contact from Joey Logano. He remained in the top ten in points throughout the year and finished 7th in the championship standings.

2017: Daytona 500 Win

Stewart-Haas Racing switched to Ford for the 2017 season, a manufacturer who had not won a Cup championship since Busch's 2004 campaign with Roush.^[35]

Busch started off 2017 with a crash in the Advance Auto Parts Clash after Jimmie Johnson got loose and spun, collecting Busch.^[36] A week later, Busch won the Daytona 500, passing Kyle Larson on the last lap.^[37] Busch struggled throughout the rest of the year, obtaining a 14th place in the standings with 6 Top-5s, 14 Top-10s and 7 DNFs.

2018: Final season at Stewart-Haas

In the summer of 2017, Busch and Stewart-Haas Racing were visibly struggling to re-sign Busch as it was announced that SHR had not "picked up the option" to re-sign Kurt. Despite this, Busch and SHR signed a one-year deal for him to continue driving their No. 41 Ford in 2018. Busch started the 2018 season with the pole at Texas. He repeated this at Michigan and New Hampshire. Busch would get his only win of the season in the night race at Bristol, snapping a 58-race winless streak and locking him in the 2018 Playoffs. His consistency had advanced him as far as the Round of 8 of the Playoffs before he was eliminated at Phoenix due to a late crash with Denny Hamlin and Chase Elliott. Busch finished the season seventh in the points standings. On December 2, 2018, Busch announced that he will not return to Stewart-Haas Racing in 2019.^[38]

2019

On December 4, 2018, it was confirmed that Busch and sponsor Monster Energy will move to the Chip Ganassi Racing No. 1 Chevrolet Camaro ZL1 in the 2019 season. As he signed a one-year deal with the team, it was believed that this would have been his final full-time season in NASCAR competition.^[39]

At the Pennzoil 400, Busch's No. 1 car had sponsorship from Star Nursery, and the car's livery was based on Busch's first NASCAR victory in the AutoZone Elite Division.^[40] He came in second to his brother Kyle at the 2019 Food City 500 with his second 1–2 finish and scored his first win with CGR at Kentucky, beating his brother Kyle on the final restart.^[41] It was the third time the Busch brothers finished 1–2, but the first time Kurt emerged the victor. Despite making the playoffs, Busch was eliminated in the Round of 16 after finishing 20th at the Charlotte Roval.^[42] On November 2, 2019, CGR officially announced that Busch has signed on with the No. 1 team for at least two more years.^[43]

2020

Busch managed to make the 2020 playoffs without winning a race by staying consistent with four top-fives and 14 top-10 finishes. He scored his 32nd career win and his first of 2020 at Las Vegas; the win secured him a spot in the Round of 8.^[44]

2021

Busch started 2021 with 1 top-five and 2 top-10 finishes in the first three races, however, his results dropped off; he would not finish in the top-10 again until the 16th race at Sonoma. He finished 6th and sparked a run of three consecutive top-eight finishes. On June 30, 2021, Justin Marks, co-founder of Trackhouse Racing Team announced that he had purchased Chip Ganassi Racing's entire NASCAR operations after the 2021 season, which left Busch as a free agent. On July 11, Kurt held off younger brother Kyle to win the Quaker State 400 at Atlanta, locking himself into the playoffs, and securing his last ever 1-2 finish against him. Busch was eliminated from the playoffs following the conclusion of the Round of 16 at Bristol.^[45] He finished the season 11th in the points standings.^[46]

2022: Last full-time season

On August 27, 2021, it was revealed that Busch will pilot the No. 45 Toyota Camry for 23XI Racing in 2022. Busch began his 2022 season with a 19th-place finish at the 2022 Daytona 500. Despite a promising start with top-five finishes at Phoenix and Atlanta, he suffered from poor finishes at COTA, Richmond, Bristol dirt, Dover, and Darlington. However, he rebounded with a win at Kansas.^[47]

Daytona 500