The 1973 Cincinnati Reds season consisted of the Reds winning the National League West with a Major League-best record of 99–63, 3+1⁄2 games ahead of the Los Angeles Dodgers, before losing the NLCS to the New York Mets in five games. The Reds were managed by Sparky Anderson, and played their home games at Riverfront Stadium.

The season started well but entered a slump, which ended on July 1, 1973, when third-string catcher Hal King hit a season-changing home run, pinch-hitting a walk off home run in the bottom of the ninth with the score at 3-1 Dodgers, two on base, and the count at 2 balls and 2 strikes. The play was credited with turning the season around, and the Reds ended the season by winning the division. The Cincinnati Enquirer called the home run one of the most dramatic in Reds history.

The Reds were coming off a devastating loss in seven games to the underdog Oakland Athletics in the 1972 World Series. The offseason did not start well for the Reds. In the winter, a growth was removed from the lung of Cincinnati's star catcher, Johnny Bench. While Bench played the entire 1973 season, his power numbers dropped from 40 home runs in 1972 to 25 in '73. He never again reached the 40 homer mark, something he accomplished in two of the three seasons prior to the surgery. Looking to expand their catching lineup due to questions about Bench, the Reds traded the Rangers Jim Merritt for Hal King.^[2][3] King became the Reds' third string catcher, playing behind starter and future Baseball Hall of Famer Bench and second stringer Bill Plummer.^[4]

Coming into the season, the defending NL Champion Reds were still favored to win the strong NL West against the likes of the Houston Astros, the Los Angeles Dodgers, and the San Francisco Giants. The Reds' lineup returned virtually intact, with the exception of third base where the Reds tried to make a third baseman out of rookie Dan Driessen, a solid hitter (.301 average) who had played mostly first base in the minor leagues. With Tony Pérez fully entrenched at first base, the Reds wanted to get Driessen's bat in the lineup and his playing time was at the expense of the anemic hitting Denis Menke (.191), although the Reds were sacrificing defense with Driessen at the hot corner. The other change was at shortstop, where Dave Concepción emerged from a 1972 timeshare with Darrel Chaney to full-time starter, finally realizing his potential in his fourth year in the majors. Concepción was outstanding both at bat and in the field and was named to the NL All-Star team. But two days before the mid-summer classic on July 22, in a game against the Montreal Expos, Concepción broke his ankle sliding into third base after moving from first base on a Menke base hit, and missed the second half of the season. Concepción was batting .287, with eight home runs, 46 RBI, 39 runs scored and 22 stolen bases, all career highs despite missing almost half the season.

The Reds had other hurdles to overcome. Cincinnati's pitching ace, Gary Nolan (15–5, 1.99 ERA in '72), suffered from a sore arm that limited him to two starts and 10 innings pitched before it was discovered he had a torn ligament in his right elbow. The injury would force Nolan to also miss the entire 1974 season. There was also an issue with centerfielder Bobby Tolan. He slumped badly to .206, became a malcontent, and had several squabbles with members of Reds management, who were still unhappy with his 1971 basketball injury that cost him that season as well as Tolan's error in Game 7 of the 1972 World Series against Oakland that was arguably the key play in that game. Tolan went AWOL for two days in August 1973, and broke team rules by growing a beard. On September 27, the team suspended Tolan for the remainder of the season, including the NLCS.

The Reds started well, and were 25–16 about a quarter of the way through the season and led the second-place Dodgers by 1+1⁄2 games on May 23. But with Tolan, Menke and Bench mired in slumps and some of the Reds starting pitchers struggling, the Reds began to flounder. Reds general manager Bob Howsam determined the Reds offense would eventually come around, but the pitching staff needed help. With Nolan sidelined indefinitely and starters Jim McGlothlin (ineffectiveness) and Roger Nelson (injuries) struggling, Howsam traded for San Diego Padres left-hander Fred Norman on June 12. At the time of the trade, the 5-foot-8 lefty was 1–7 for the last-place Padres, but Norman would go 12–6 in 24 starts for the Reds to provide a major boost.

On July 1, 1973, the Reds were in a slump and trailing their National League Western Division rivals the Los Angeles Dodgers by 11 games in the standings; they had lost the previous night's game 8–7 in the 13th inning after starting with a 5–1 lead.^[5] The first game of a Dodgers double header at home was 3–1 Dodgers in the bottom of the ninth with two on base. Hal King, who had had only a single hit in his 10 at-bats for the Reds, was nevertheless known as a power hitter, and he had hit a grand slam against Don Sutton's screwball previously while playing for the Braves.^[5] Reds Manager Sparky Anderson sent him in to bat for Plummer.^[3]

The count was two balls and two strikes when King hit a walk-off home run, again against Sutton's screwball.^[6][7][3][5] King tore his cleats with the force of the hit.^[3][5] In the moment, Reds play-by-play announcer Al Michaels predicted, "Boy, I tell you, if anything can turn a season around it is that play right there."^[8] King's home run was cited by Anderson as a turning point in the season.^[9] He told the Cincinnati Enquirer, “It was one of those things that when it happens you immediately think, ‘This is going to turn us around.' ”^[3] Nearly fifty years later in 2019 the Enquirer called it "one of the most dramatic home runs in franchise history".^[5] According to Sports Illustrated, after King's hit, "[the Reds'] drive became a relentless thing" and "[Pete] Rose and most of the Reds consider [the game] they played on July 1 against Los Angeles as the turning point of their season.^[10]

Starting with the win on King's home run, the Reds gained momentum. They won the second game of the double header when Tony Pérez singled in the game-winner off knuckleball specialist Charlie Hough in the bottom of the 10th as the Reds won 3–2. They won against the Dodgers again the following day, won eight of their next nine games; by July 10, they had cut the Dodgers' lead to 4+1⁄2 games.^[7][4][3]

Both teams stayed close throughout the season, but on Aug. 29, the Reds beat Pittsburgh, 5–3, to begin a seven-game winning streak. After losing two to the Braves, the Reds began another seven-game winning streak to gain some space between the Dodgers. Los Angeles came into Cincinnati for a two-game series, Sept. 11–12, trailing the Reds by 3 games with 18 left on the schedule. A two-run home run by rookie Ken Griffey was the big hit in the Reds' 6–3 victory on Sept. 11, and the Reds completed the sweep the next day as Jack Billingham hurled a complete-game and, the typically poor hitter (.065 average), also belted a bases-clearing double off LA starter Claude Osteen in a 7–3 victory. The Dodgers left Cincinnati trailing by five games. On Sept. 24, the Reds beat San Diego, 2–1, to clinch their second-straight division title and third in four years. It sent the Reds to the 1973 NLCS against the New York Mets.

The Reds offense was led by Pete Rose (team-record 230 hits, 115 runs scored, an NL best .338 batting average), Joe Morgan (116 runs, 26 home runs, 82 RBI, 67 stolen bases, .290 avg.) and Perez (.314, 27, 101). Rose was voted the National League MVP, while Morgan finished fourth and Perez seventh in a vote by the Baseball Writers' Association of America.

Jack Billingham emerged as the staff ace, leading the National League in both innings pitched (293.1) and shutouts (7) to go with 19 victories, while young lefty Don Gullett won 11 of his last 12 decisions to finish 18–8.

Future stars Griffey and George Foster also played well in short stays with the Reds. Griffey batted .384 in 86 at bats in his major league debut, while Foster hit .282 and smacked four home runs in just 39 at bats. Journeyman third-string catcher Hal King also emerged as an unsung hero. King hit three pinch hit home runs, all of which either tied or won games late including a three-run home run off Los Angeles Dodger starter Don Sutton on July 1 to win a game for the Reds.

• November 27, 1972: Nardi Contreras was drafted from the Reds by the New York Mets in the 1972 minor league draft.^[11]
• November 30, 1972: Hal McRae and Wayne Simpson were traded by the Reds to the Kansas City Royals for Roger Nelson and Richie Scheinblum.^[12]
• December 1, 1972: the Rangers traded Hal King with Jim Driscoll to the Reds for Jim Merritt.^[2]
• March 27, 1973: Mel Behney was traded by the Reds to the Boston Red Sox for Andy Kosco and Phil Gagliano.^[13]

The Reds lost the National League Championship Series to the Mets 3 games to 2 despite heroics by Rose and Bench in Game 1 and Rose again in Game 4. Rose's eighth-inning home run against Tom Seaver tied the score at 1–1 and Bench won it in the 9th with another solo home run. Rose also hit a game-winning home run in the 12th-inning to tie the series at 2–2. During Game Three of the series, Rose got into a fight with the popular Mets shortstop Bud Harrelson while trying to break up a double play; the fight resulted in a bench-clearing brawl. The umpires threatened the Mets with forfeiting the game, after fans responded by hurling garbage from the stands at Rose, causing the Reds team to leave the field until order was restored.

• Pete Rose – National League Most Valuable Player
• Pete Rose – National League Batting Champion

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