Casey O'Neill

Casey O'Neill is a Scottish-Australian mixed martial artist fighting in the UFC women's flyweight division. Known for her aggressive grappling and relentless pace, she has built a reputation as a finisher with 6 stoppages in 11 wins. As of 2026, she is ranked #15 in the Meta UFC women's flyweight rankings and coming off a first-round knockout of Gabriella Fernandes. Fans appreciate her never-back-down style and the way she wears her heart on her sleeve inside the Octagon. [edit]

Casey O'Neill was born in Irvine, Scotland, and grew up in Kilmarnock before her family moved to Australia's Gold Coast when she was 10. Her father, Cam, was a professional kickboxer, and she started training in kickboxing at age four. At 13, she added Brazilian jiu-jitsu and MMA to her regimen. Her father also promoted an MMA show, and Casey begged him for years to let her fight. He finally relented, and she compiled a 5-2 amateur record, losing her first two bouts, then winning five straight, all by finish. Before turning pro, she worked as a barista. She chose to pursue fighting full-time rather than attend college, a decision that paid off when she earned a UFC contract on Dana White's Contender Series. [edit]

O'Neill made her professional MMA debut in 2018 and quickly became a two-time strawweight champion on the Australian regional scene. In 2020, she competed on Dana White's Contender Series and secured a UFC contract. Her UFC debut came in February 2021, stopping Shana Dobson via TKO. She followed with a submission win over Lara Procopio and a TKO of Antonina Shevchenko, earning attention as a rising prospect. A split decision win over veteran Roxanne Modafferi at UFC 271 pushed her to 4-0 in the promotion. In 2023, she suffered her first losses, a decision to Jennifer Maia and a submission to Ariane Lipski. She rebounded in 2024 with a unanimous decision over Luana Santos. After moving her training camp from Xtreme Couture to Fight Ready, she knocked out Gabriella Fernandes in the first round at UFC Fight Night in March 2026. She is scheduled to face Eduarda Moura at UFC 331. [edit]

O'Neill presents a confident, determined persona, embodied in her nickname 'King.' Her fighting style is kickboxing-based but she is known for her aggressive grappling and relentless pace, which have made her a fan favorite. She is active on Instagram at @kingcaseymma, where she shares training updates and glimpses of her life. Fans appreciate her authenticity and the way she wears her emotions during fights. She has not developed a formal fandom name, but her supporters rally behind her never-quit attitude. [edit]

Casey O'Neill's fanbase is defined by a collective reverence for the 'King' persona, a moniker that has eclipsed older nicknames like 'The Queen of Violence' to become the primary anchor of her identity. Supporters rally around a narrative of resilience, particularly following her triumphant return from a 19-month layoff and the viral revelation that she competed at UFC Seattle wearing two left-handed gloves. This moment of absurdity, quickly overshadowed by a thunderous first-round knockout, humanized the fighter and turned a potential disaster into a legendary piece of MMA folklore. The audience operates primarily through standard digital channels rather than formalized grassroots campaigns, with no single organized group or specific fandom name emerging to unite them. Fans connect deeply with O'Neill's authenticity, celebrating her willingness to share vulnerabilities alongside her aggressive in-cage performance. As of August 2026, iFANN's Global Fame Engine has evaluated this person, but they do not currently hold a placement in the published rankings (Global Top 1,000 or a Top-100 scope list). Consequently, Casey O'Neill is not ranked within the current Global Top 1,000 most famous people nor does she appear on any Top-100 scope list.[edit]

Her nickname 'King' was bestowed by her coach and stuck due to her dominant mentality, distinguishing her from other fighters who might use titles like 'Queen.' She holds a brown belt in Brazilian jiu-jitsu under Casey Halstead, favoring joint locks as her go-to grappling technique while relying on boxing for striking. Before her professional career took off, she worked as a barista, though fighting was always her only planned path. Her amateur record tells a story of early struggle followed by dominance; she lost her first two fights before winning five consecutive bouts, all by finish. A defining legend in her modern mythology involves her return from a 19-month injury layoff where she defeated Gabriella Fernandes via first-round knockout. In a bizarre twist that became instant lore, O'Neill revealed shortly after the fight that she had competed wearing two left-handed gloves, turning a safety blunder into a viral moment of resilience.[edit]

O'Neill's father, Cam, was a professional kickboxer and the one who introduced her to martial arts. He also promoted an MMA show when she was 13. Her mother's name is not publicly known. She has not disclosed any siblings. As of 2026, she is single with no children and lives in Las Vegas, Nevada, where she trains. She has not publicly mentioned any pets. [edit]

O'Neill's father Cam, a former professional kickboxer, trained her from a young age and started an MMA show that sparked her interest. She earned her brown belt in Brazilian jiu-jitsu under Casey Halstead. Key opponents include Antonina Shevchenko (win), Roxanne Modafferi (win), Jennifer Maia (loss), Ariane Lipski (loss), Luana Santos (win), and Gabriella Fernandes (win). She is scheduled to face Eduarda Moura at UFC 331. [edit]

No public romantic relationships have been confirmed for Casey O'Neill. As of 2026, she is reported as single with no known partners. She has not publicly discussed her dating life, and there are no credible reports of past relationships. [edit]

No credible net worth estimates for Casey O'Neill are publicly available. As a UFC fighter, her income comes from fight purses, performance bonuses, and sponsorship deals. Her most recent fight in March 2026 likely earned her a base salary plus a win bonus, though exact figures are not disclosed. She trains at Fight Ready in Las Vegas and lives modestly. Without major endorsement deals or business ventures, her net worth is not widely reported. [edit]