History of Sean O'Malley (fighter) in Timeline

Sean O'Malley is an American professional mixed martial artist competing in the UFC's Bantamweight division. He is the former UFC Bantamweight Champion. As of May 13, 2025, he holds the #1 ranking in the bantamweight division and is #14 in the UFC men's pound-for-pound rankings.

Sections (2)

Full Timeline Career & Achievements

October 24, 1994: Sean O'Malley's Birth

On October 24, 1994, Sean Daniel O'Malley was born. He is an American professional mixed martial artist.

December 1, 2017: Promotional Debut

On December 1, 2017, Sean O'Malley made his promotional debut against Terrion Ware at The Ultimate Fighter 26 Finale and won via unanimous decision.

March 3, 2018: Fight against Andre Soukhamthath

On March 3, 2018, Sean O'Malley fought Andre Soukhamthath at UFC 222 and won by unanimous decision, despite a foot injury. The fight earned both a Fight of the Night bonus.

October 6, 2018: O'Malley Out of Fight

On October 6, 2018, Sean O'Malley was expected to fight José Alberto Quiñónez at UFC 229, but O'Malley announced his withdrawal on September 30 due to a potential Anti-Doping Policy violation.

March 2019: Eligibility to Return

In March 2019, Sean O'Malley became eligible to return to fighting after a suspension for testing positive for ostarine.

June 21, 2019: O'Malley Withdraws from Bout

On June 21, 2019, Sean O'Malley announced his withdrawal from the bout against Marlon Vera scheduled for July 6, 2019, due to a failed test for ostarine. The Nevada State Athletic Commission suspended him and he was suspended for 6 months by USADA.

July 6, 2019: Withdrawal from Bout

On July 6, 2019, Sean O'Malley was scheduled to face Marlon Vera at UFC 239, but withdrew on June 21 due to a failed test for ostarine and was suspended.

December 12, 2019: Competed at Quintet: Ultra

On December 12, 2019, Sean O'Malley competed at Quintet: Ultra as a member of Team UFC. He submitted Takanori Gomi but was then submitted by Héctor Lombard. Team UFC won the tournament.

March 7, 2020: Fight against José Alberto Quiñonez

On March 7, 2020, Sean O'Malley fought José Alberto Quiñonez at UFC 248 and won via TKO in the first round, earning a Performance of the Night award.

June 6, 2020: Fight against Eddie Wineland

On June 6, 2020, Sean O'Malley faced Eddie Wineland at UFC 250 and won via one-punch knockout in the first round, earning the Performance of the Night award.

August 15, 2020: Fight against Marlon Vera

On August 15, 2020, Sean O'Malley faced Marlon Vera at UFC 252 and lost via TKO in round one. He was later diagnosed with drop foot due to a leg kick.

September 20, 2020: Competed at Grappling Industries Phoenix

On September 20, 2020, Sean O'Malley competed at Grappling Industries Phoenix in the 155lbs Advanced No-gi division, placing third.

December 20, 2020: Challenge by James Gallagher

On December 20, 2020, James Gallagher challenged Sean O'Malley to a grappling match at the SUG event, after an open challenge by Chael Sonnen on O'Malley's behalf. O'Malley reportedly declined the matchup.

2020: Birth of Daughter

In 2020, Sean O'Malley and his wife had a daughter.

March 27, 2021: Fight against Thomas Almeida

On March 27, 2021, Sean O'Malley faced Thomas Almeida at UFC 260 and won via knockout in the third round, earning a Performance of the Night award.

July 10, 2021: Fight against Kris Moutinho

On July 10, 2021, Sean O'Malley faced Kris Moutinho at UFC 264 and won via TKO in round three, earning the Fight of the Night award.

December 11, 2021: Fight against Raulian Paiva

On December 11, 2021, Sean O'Malley faced Raulian Paiva at UFC 269 and won via TKO in round one, earning his fourth Performance of the Night bonus award.

July 2, 2022: Fight against Pedro Munhoz

On July 2, 2022, Sean O'Malley faced Pedro Munhoz at UFC 276. The fight was declared a no contest after an accidental eye poke.

October 22, 2022: Fight against Petr Yan

On October 22, 2022, Sean O'Malley faced Petr Yan at UFC 280 and won via split decision in a controversial fight that received the Fight of the Night bonus. Sherdog website gave this fight "2022 Robbery of the Year Award".

August 19, 2023: UFC Bantamweight Championship Win

On August 19, 2023, Sean O'Malley faced Aljamain Sterling for the UFC Bantamweight Championship at UFC 292 and won the title by second-round TKO, earning a Performance of the Night bonus.

March 9, 2024: First Title Defense against Marlon Vera

On March 9, 2024, Sean O'Malley defended his title against Marlon Vera at UFC 299, winning via unanimous decision and earning his sixth Performance of the Night bonus award.

September 14, 2024: Loss to Merab Dvalishvili

On September 14, 2024, Sean O'Malley faced Merab Dvalishvili at UFC 306 and lost by unanimous decision. He later revealed on September 16 that he had a torn labrum and would undergo surgery.