DEEP Choi started getting noticed in the MMA world after making his DEEP debut in June 2010, when he faced Yusuke Kagiyama. Choi lost his Deep debut via split decision. After a short stint on the independent circuit, Choi returned to DEEP in September 2010, facing Atsuhiro Tsuboi. He won by TKO in the first round. He went undefeated in his next fights in MMA, beating various fighters like Mitsuhiro Ishida, Kosuke Omeda, and Nobuhiro Obiya. Before being released to fight in the UFC, Choi fought for DEEP one last time, on June 15, 2013, when he faced Japanese prospect Shoji Maruyama. He won via TKO in the second round.
Sengoku Raiden Championship While fighting for DEEP, Choi also signed with Sengoku Raiden Championship. He had his first fight at SRC: Sengoku Raiden Championship 13, when he faced Ikuo Usuda. Choi won via split decision. A few months later, Choi was slated to face
Masanori Kanehara at SRC: Sengoku Raiden Championship 15. However, three weeks before the event, Choi suffered an injury and the fight was taken off the card.
Ultimate Fighting Championship In November 2013, following a nine-fight winning streak, Choi signed a contract to fight with the
UFC to compete in their featherweight division. Choi was scheduled to face
Sam Sicilia on May 24, 2014, at
UFC 173. However, Choi pulled out of the bout with an injury. Choi ultimately made his debut when he faced Juan Puig on November 22, 2014, at
UFC Fight Night 57. He won the fight via TKO just 18 seconds into the first round. A rescheduled bout with Sam Sicilia was expected to take place on July 15, 2015, at
UFC Fight Night 71. However, Choi pulled out of the fight in late June for undisclosed reasons. The bout with Sicilia was scheduled a third time and took place on November 28, 2015, at
UFC Fight Night 79. Choi won the fight via knockout in the first round. The win also earned him his first
Performance of the Night bonus award. Choi next faced
Thiago Tavares on July 8, 2016, at
The Ultimate Fighter 23 Finale. He won the fight via knockout in the first round. The win earned him a
Performance of the Night bonus award. Choi faced
Cub Swanson on December 10, 2016, at
UFC 206. He lost the fight via unanimous decision. The fight was nominated for
Fight of the year by the
World MMA Awards and
ESPN. Both participants were awarded
Fight of the Night. During
UFC 273 broadcast in April 2022 it was announced that the fight will be inducted to the
UFC Hall of Fame Fight Wing class of 2022. Choi was briefly linked to a bout with
Renan Barão which was expected to take place on April 15, 2017, at
UFC on Fox 24. However, as the announcement of the pairing began to circulate, Choi declined the bout, and as a result, Barao is expected to be rescheduled against a different opponent, possibly at another event. Choi was expected to face
Andre Fili on July 29, 2017 at
UFC 214. However, Choi pulled out of the fight on June 14 citing an injury and was replaced by promotional newcomer
Calvin Kattar. Choi next faced
Jeremy Stephens on January 14, 2018 at
UFC Fight Night: Stephens vs. Choi. He lost the fight via TKO in the second round. Both participants were awarded
Fight of the Night. Choi faced
Charles Jourdain on December 21, 2019 on
UFC on ESPN+ 23. After knocking Jourdain down in the first round, Choi eventually lost the fight via TKO in the second round. Both participants were awarded
Fight of the Night awards. Choi was scheduled to face Danny Chavez on July 31, 2021 at
UFC on ESPN 28. However, Choi had to pull out of the bout due to injury. Returning after a three-year layoff, Choi faced
Kyle Nelson on February 4, 2023, at
UFC Fight Night 218. After a point deduction in the third round due to a headbutt, the fight ended in a majority draw. 9 out of 11 media outlets scored the fight as a win for Choi. Choi faced
Bill Algeo on July 20, 2024 at
UFC on ESPN 60. He won the fight by technical knockout in the second round. Choi faced
Nate Landwehr on December 7, 2024 at
UFC 310. He won the fight by technical knockout via ground punches and elbows in the third round. Choi was scheduled to face
Daniel Santos on September 27, 2025 at
UFC Fight Night 260. However, Choi withdrew for unknown reasons and was replaced by Yoo Joo-sang. Choi was scheduled to face
Gavin Tucker on April 18, 2026 at
UFC Fight Night 273. However, Tucker had not signed a bout agreement and subsequently announced his retirement from mixed martial arts. Choi's bout with Daniel Santos was re-scheduled to take place on May 9, 2026 at
UFC 328. However, it was later moved to
UFC Fight Night 276 one week later on May 16, 2026 for unknown reasons. == Personal life ==