Early career Johnson originally began training in
mixed martial arts (MMA) as a hobby, continuing for two years before being invited to
AMC Pankration, where he would meet MMA pioneer
Matt Hume, who had been scouting Johnson and organized the event where Johnson made his MMA debut. Johnson showed good kickboxing throughout but was unable to defend the many takedowns executed by Pickett. Johnson lost via unanimous decision.
Joe Rogan predicted during the fight that, should the WEC implement a flyweight division, Johnson would be highly effective, as he was a relatively small bantamweight. Johnson was expected to face Clint Godfrey on September 30, 2010, at
WEC 51. However, Godfrey was forced off the card and replaced by WEC newcomer
Nick Pace. Johnson defeated Pace via unanimous decision, handing Pace his first MMA loss. Johnson defeated
Damacio Page via third-round submission on November 11, 2010, at
WEC 52. Johnson faced Japanese fighter
Norifumi "KID" Yamamoto on February 5, 2011, at
UFC 126 in his UFC debut, Johnson won via unanimous decision. Johnson was scheduled to face
Renan Barão on May 28, 2011, at
UFC 130. However, Johnson faced
Miguel Torres after Torres's opponent, Brad Pickett, was forced off the card with an injury. Despite breaking his fibula early in the second round from a checked leg kick, Johnson used his superior wrestling to control Torres and won a 29–28 unanimous decision victory, even though he was swept into full mount a record-breaking 6 times during the fight. Johnson fought
Dominick Cruz on October 1, 2011, at
UFC Live: Cruz vs. Johnson for the UFC bantamweight title, losing by unanimous decision. Johnson was briefly linked to a bout with
Eddie Wineland on January 28, 2012, at the UFC's second event on Fox. However, Johnson was pulled from the bout to take part in a four-man
flyweight tournament to determine the UFC's first
UFC Flyweight Champion. Johnson faced
Ian McCall on March 3, 2012, in the first round of the
Flyweight Tournament at
UFC on FX 2. This fight was the first flyweight bout in UFC history. The fight with McCall was announced as a majority decision win for Johnson. Later, in the post-fight press conference, UFC president
Dana White announced that the athletic commission
made a mistake when scoring the match and that officially the bout was scored a majority draw (28–28, 29–29, and 29–28 Johnson). A rematch with McCall took place on June 8, 2012, at
UFC on FX: Johnson vs. McCall. Johnson won the fight via unanimous decision to progress to the final round of the tournament.
UFC Flyweight Champion (2012–2018) Johnson faced
Joseph Benavidez in the finals of the UFC Flyweight Tournament on September 22, 2012, at
UFC 152. Johnson defeated Benavidez via split decision to become the inaugural
UFC Flyweight Champion. Johnson fought
John Dodson on January 26, 2013, at
UFC on Fox: Johnson vs. Dodson. Johnson won the fight via unanimous decision in a bout that earned both participants
Fight of the Night honors. Johnson was expected to face
John Moraga on April 13, 2013, at
The Ultimate Fighter 17 Finale. However, Johnson was forced out of the bout with an injury, and Moraga was pulled from the event as well. The bout with Moraga eventually took place on July 27, 2013, at
UFC on Fox: Johnson vs. Moraga, where Johnson was looking to defend his title for a second time. Johnson won via an armbar submission late in the fifth round. The win also earned Johnson his first
Submission of the Night bonus award. A rematch with Joseph Benavidez was expected for November 30, 2013, at
The Ultimate Fighter 18 Finale. However, the bout was moved to December 14, 2013, at
UFC on Fox 9 after that event's headliner was postponed due to injury. However, the bout was shifted to September 27, 2014, at
UFC 178 after that event's headliner was cancelled due to injury. Johnson won the fight via submission due to a kimura in the second round. This marked Johnson's fifth title defense and the first time that a kimura was used to end a fight in a UFC championship title bout. Johnson faced
Kyoji Horiguchi at
UFC 186, winning the one-sided fight via an armbar submission at 4:59 of the fifth round, resulting in the latest finish in UFC history. This win also secured Johnson a
Performance of the Night bonus award. A rematch with John Dodson took place on September 5, 2015, at
UFC 191. In a largely one-sided affair, Johnson won the fight via unanimous decision. Johnson faced Olympic Gold Medalist
Henry Cejudo on April 23, 2016, at
UFC 197. He won the fight via TKO in the first round after dropping Cejudo with a variety of strikes. The win earned Johnson his second
Performance of the Night bonus. Johnson next faced
Tim Elliott on December 3, 2016, at
The Ultimate Fighter 24 Finale. Despite being a heavy favorite, Johnson was taken down for the first time as a flyweight and nearly submitted with a d'arce choke in the first round. He went on to win the remaining rounds, and defended the Championship via a decisive unanimous decision. Johnson faced
Wilson Reis on April 15, 2017, at
UFC on Fox 24. He won by armbar submission in the third round and subsequently received a Performance of the Night bonus. With the win, Johnson tied
Anderson Silva for most consecutive title defenses (ten) in UFC history. In July 2017, Johnson won an
ESPY Award for Fighter of The Year. Johnson was briefly linked to an August 2017 fight with
T.J. Dillashaw. He was scheduled to face
Ray Borg on September 9, 2017, at
UFC 215. In turn, the fight was canceled a day before the event, as Borg was forced to withdraw from the fight on Thursday evening due to illness. According to multiple sources, Borg has been battling an illness that week and was deemed unfit to fight by UFC doctors. The bout was quickly rescheduled and took place at
UFC 216. Johnson won the fight via suplex-to-armbar in the fifth round. This win earned him the
Performance of the Night award and set the 11th successful title defense record, surpassing former middleweight champion Anderson Silva's record of 10 in the UFC. Johnson's win was called the best submission of the year from publications such as Sherdog, MMA Mania.com, and The MAC Life. Johnson faced
Cejudo in a rematch at
UFC 227 on August 4, 2018, for the
UFC Flyweight Championship title. After a record 11 consecutive successful title defenses, Johnson's championship reign came to an end via a split decision loss to Cejudo. This fight earned him the
Fight of the Night award. 13 of 25 media outlets scored the bout in favor of Cejudo, while 12 scored it for Johnson.
Hall of Fame (2026) During
UFC Fight Night 271's broadcast in March 2026, Johnson was announced as the next "modern wing" inductee into the
UFC Hall of Fame, with the ceremony scheduled for International Fight Week in Las Vegas on July 9, 2026.
ONE Championship On October 27, 2018, Johnson was traded to ONE Championship for former
ONE Welterweight Champion Ben Askren. Johnson was expected to make his promotional debut in the first quarter of 2019.
ONE Flyweight Grand Prix On November 7, 2018, it was announced that Johnson would be one of eight participants in the
ONE Flyweight World Grand Prix. On December 19, 2018, it was announced that Johnson will be facing
Yuya Wakamatsu at
ONE Championship: A New Era on March 31, 2019, in the promotion's inaugural event in Japan. In his ONE Championship debut, Johnson defeated
Yuya Wakamatsu via a guillotine choke submission in the second round. Johnson's second ONE Championship fight took place at
ONE Championship: Dawn of Heroes on August 2, 2019. He faced Tatsumitsu Wada in the semi-finals of the ONE Flyweight Grand Prix and won the fight by unanimous decision to advance to the finals. Johnson then faced
Danny Kingad at
ONE Championship: Century in the finals of the
ONE Championship Flyweight Grand-Prix on October 12, 2019. He defeated Kingad in a dominant unanimous decision victory and became the ONE Flyweight World Grand Prix Champion.
ONE Flyweight title shot After claiming the Grand Prix victory, Johnson was set to challenge
ONE Flyweight Champion Adriano Moraes at
Infinity 1. The fight was postponed due to the
COVID-19 pandemic. Johnson faced Moraes at
ONE on TNT 1 on April 7, 2021. The event was held at the
Singapore Indoor Stadium in
Kallang,
Singapore and was broadcast on
TNT during US
prime time. He lost the bout via KO in round two by a knee and punches.
Special-rules fight with Rodtang Jitmuangnon On September 15, 2021, it was announced that Johnson would fight
Rodtang Jitmuangnon, the reigning
ONE Flyweight Muay Thai World Champion and considered by many to be the current best pound-for-pound Muay Thai fighter. The fight was contested under special rules, with rounds 1 and 3 being fought under the ONE Muay Thai ruleset, and rounds 2 and 4 being fought under the ONE MMA ruleset. However, due to the pandemic shutdowns, the event was rescheduled for
ONE: X on March 26, 2022. Johnson won the bout via a rear-naked choke submission in the second round.
ONE Flyweight Champion (2022–2023) On June 2, 2022, it was reported that Johnson would rematch
Adriano Moraes for the
ONE Flyweight Championship at
ONE on Prime Video 1. Johnson would go on to defeat Moraes by knockout via a flying knee in the fourth round to capture the
ONE Flyweight Championship. This win earned him the
Performance of the Night award. The trilogy bout between Johnson and Moraes was held on May 5, 2023, at
ONE Fight Night 10. Johnson won the bout by unanimous decision. Johnson announced his retirement from the sport on September 6, 2024, at ONE 168. Following his retirement speech, ONE CEO
Chatri Sityodtong announced that Johnson was the first inductee into the ONE Hall of Fame. ==Grappling career==