Haney vs. Santiago

On the undercard of KSI vs. Logan Paul II in November 2019, Haney made his first title defense against Alfredo Santiago (12–0), and won by unanimous decision. He injured his shoulder during the fight, requiring surgery that would keep him out until the summer of 2020.^[12] He maintained the title "champion in recess."^[13]

Haney vs. Gamboa

On October 2, 2020, it was revealed that Haney would make the second defense of his WBC lightweight title against the former unified featherweight titlist Yuriorkis Gamboa, on November 7, 2020. The bout was held at the Hard Rock Live in Hollywood, Florida, and was broadcast by DAZN.^[14][15] Most media members predicted an easy victory for the reigning champion,^[16][17][18] which was reflected in the betting odds as well, with most odds-makers having Haney as a -5000 favorite.^[19] Haney won the fight by a dominant unanimous decision, with two of the judges awarding him every single round of the fight, while the third judge scored it 118–109 in favor of Haney. Gamboa was deducted a point in the eleventh round for holding. Haney out-landed Gamboa 133 to 84 in total punches, and 82 to 63 in power punches landed.^[20]

Haney vs. Linares

In what was seen by many as Haney's toughest test of his career so far, Haney made the third defense of his WBC lightweight title against former three-weight world champion Jorge Linares on May 29, 2021.^[21] He won by unanimous decision with the judges scoring the bout 116–112, 116–112, 115–113 in his favor.^[22] Haney controlled the action for most of the fight, but was hurt when Linares caught him with a powerful right-left combination toward the end of the tenth round. Haney survived the final two rounds largely by tying Linares up and negating his opponent's attempts at trying to engage with him. The crowd voiced their displeasure with what they perceived as excessive clinching by booing Haney when he jumped up on the ropes in celebration immediately after the final bell, as well as booing during the announcement of the official decision.^[22]

Haney vs. Diaz

Joseph Diaz had been scheduled to defend his WBC interim lightweight title against Ryan García on November 27, 2021, until García withdrew from the fight due to a hand injury.^[23] This led to back and forth on social media between Haney and Diaz, culminating in an official announcement on November 3 that Diaz would now be challenging for Haney's full world title on December 4, instead of defending his interim title against García.^[24] On the night, Haney defeated Diaz by unanimous decision, with scores of 117–111, 117–111, 116–112 in his favor. After the fight, the victor announced his desire to face unified champion George Kambosos Jr. for all four major world titles in the lightweight division, stating, "Let's do it for all the belts. The real undisputed."^[25]

Haney vs. Kambosos Jr.

In front of a sold-out crowd in Melbourne, Australia in June 2022, Haney defeated George Kambosos Jr. by outpointing and outboxing the Australian fighter to become the first undisputed lightweight champion in the four-belt era. The judges scored the bout 116–112, 116–112, 118–110, all in favor of Haney.^[26] The deal for the fight included an automatic rematch clause which Kambosos exercised, with the rematch occurring in October 2022 in Australia.^[27][28]

Haney vs. Kambosos Jr. II

Devin Haney and George Kambosos Jr. met in their rematch at Rod Laver Arena in Melbourne, Australia on October 16, 2022.^[29] Haney defeated Kambosos via unanimous decision with the scores of 118–110 (twice) and 119–109.^[30]

Haney vs. Lomachenko

On March 29, 2023, it was confirmed that Haney would make a second defense of his undisputed lightweight titles against former unified lightweight champion Vasiliy Lomachenko on May 20, 2023, at the MGM Grand Garden Arena in Paradise, Nevada, U.S.^[31]

With Lomachenko coming in as the underdog for the first time in his career, much of the bout turned out to be closely contested, with both men finding success, Lomachenko scoring with clean combinations to the head, while Haney countered consistently with solid body shots. Late in the fight, Lomachenko became increasingly dominant, finding particular success in the 10th and 11th rounds. However, Haney rallied to win the final round on all three judges' scorecards.^{[32][33][34][35]}

Ultimately, Haney won the fight and retained his world titles via unanimous decision, with scores of 116–112, 115–113 and 115–113.^[36] However, the decision was greatly disputed, as many onlookers felt Lomachenko had done enough to win, including fellow boxers Shakur Stevenson and Jorge Linares, who had previously predicted a Haney victory.^{[37][33][38][39][40]} Judge Dave Moretti's scorecard, giving round 10 to Haney despite Lomachenko dominating that round, was heavily criticised.^[32][41] Others argued that as the fight had been close, a narrow result for Haney was not unreasonable.^[35] Compubox punch stats suggested Haney had landed 110 of 405 punches thrown (27%), while Lomachenko landed 124 of 564 (22%), with both boxers outlanding the other in five rounds each, the other two rounds being even.^[34] Lomachenko believed he had won and his team subsequently stated they would file an appeal regarding the result. Haney on his part praised Lomachenko, calling him his toughest opponent yet.^[37][33]

Regardless of the result, the fight and the performances of both men were widely praised. It was described by multiple accounts as "thrilling", with Lomachenko's display against a substantially younger and larger opponent being highly lauded.^[33][35] Afterwards, Haney was fined $25,000 for violently shoving Lomachenko during the weigh-in faceoffs.^[42][43]

Haney vs. Prograis

On December 9, 2023, in an almost sold-out Chase Center in San Francisco, California, Haney moved up a weight class and challenged Regis Prograis for the WBC super lightweight title.

Haney produced a masterclass performance, dominating Prograis from start-to-finish. With the exception of a cagey first round, Haney dominated every round going forward. A knockdown in the third with a right hand cemented his supremacy. By the middle rounds, Prograis looked battered and bruised and seemed bereft of ideas. Haney staggered Prograis several more times in the middle rounds, but seemed reluctant to go for the finish and instead, relied on his winning formula of attacking and retreating.

All three judges scored the fight 120–107 as Haney added another belt to become a two-weight world champion at the age of 25.^[48]

Haney vs. Garcia

Haney vs Ryan Garcia was signed^[49] for April 20, 2024 in Brooklyn, New York, for the WBC super lightweight title.^[50] Two days before the fight, Garcia agreed to a wager with Haney that Garcia would pay $500,000 for every pound over the limit should he miss weight. Garcia weighed in over the limit at 143.2 lbs. and would forfeit up to $600,000 of his purse to Haney.^[51]

Haney was knocked down three times by Garcia during the 12 round contest, and lost via majority-decision.^[52] One judge scored the bout 112-112 but was overruled by scores of 114-110 and 115-109 for Garcia, who outlanded Haney 106-87 in total punches and 95-45 in power punches, according to Compubox.

Garcia (25-1, 20 KOs) was not eligible to win Haney's (31-1, 15 KOs) WBC junior welterweight title after he weighed 143.2 pounds Friday for the 140-pound contest. ^[53]