Casey O’Neill Bio
Casey O’Neill is a Scottish and Australian professional mixed martial artist born on October 7, 1997. She competes in the women’s Flyweight division of the Ultimate Fighting Championship (UFC) and is recognized for her striking skills developed through kickboxing. Since her professional debut in 2019, O’Neill has quickly established herself as a rising talent in the UFC.
Early Life and Background
Casey O’Neill was born in Irvine, Scotland, and spent her early childhood in Kilmarnock. Her father, Cam, was a professional kickboxer, which influenced her early introduction to martial arts. She began training in kickboxing at the age of four and later expanded her skills to Brazilian jiu-jitsu at age 13.
At ten, O’Neill moved with her family to Australia’s Gold Coast, where she attended Coombabah State High School. Her early exposure to combat sports and disciplined training laid the foundation for her future MMA career. Despite early setbacks in amateur fights at ages 15 and 16, she committed to improving her skills and returned stronger at 19, winning five consecutive amateur bouts before turning professional at 21.
Path to MMA
O’Neill’s path to professional MMA began with dedicated training and competing in the amateur circuit. After honing her skills, she relocated to Phuket, Thailand, in 2019 to train at the renowned Tiger Muay Thai gym. This move marked a significant step in her development, exposing her to high-level coaching and competition.
Her early professional fights were primarily in Australia, where she secured multiple wins before stepping onto the international stage with UAE Warriors. Her striking background and evolving grappling skills helped her transition successfully to the professional ranks.
Casey O’Neill Career
Early Career (2019–2020)
Casey O’Neill made her professional MMA debut on April 5, 2019, at Eternal MMA 43, winning by unanimous decision against Amira Hafizović. She continued to build momentum with victories over Jada Ketley, Miki Motono, and Caitlin McEwen. Despite missing weight in one bout, she demonstrated resilience and skill, culminating in a knockout win over Christina Stelliou at UAE Warriors 13 in September 2020.
During this period, O’Neill trained with Tiger Muay Thai, refining her striking and grappling. Her performances caught the attention of the UFC, leading to her signing with the promotion.
Ultimate Fighting Championship Breakthrough (2021–Present)
O’Neill debuted in the UFC on February 20, 2021, at UFC Fight Night: Blaydes vs. Lewis, securing a second-round knockout victory over Shana Dobson. She followed this with a submission win via rear-naked choke against Lara Procópio in June 2021, showcasing her growing grappling prowess.
In October 2021, she defeated Antonina Shevchenko by technical knockout, earning the Performance of the Night award. O’Neill continued her winning streak with a split decision victory over Roxanne Modafferi at UFC 271 in February 2022, a fight widely scored in her favor despite one dissenting judge.
Injuries impacted her schedule, including a torn ACL that forced her withdrawal from UFC 276. She returned to face Jennifer Maia at UFC 286 in March 2023 but suffered her first professional loss by unanimous decision. Later that year, she lost to Ariane Lipski via armbar submission at UFC 296.
Fight Ready Era (2024–Present)
O’Neill transitioned to training with Fight Ready, a move that coincided with her competing in the Flyweight division since 2020. In August 2024, she defeated Luana Santos by unanimous decision at UFC 305 after a late opponent change. This victory marked a positive step in her comeback and ongoing career development.
Fighting Style and Strengths
Casey O’Neill is known for her kickboxing-based striking style, complemented by a brown belt in Brazilian Jiu-Jitsu. Her reach of 175 cm and height of 168 cm provide advantages in stand-up exchanges. She combines aggressive striking with submission skills, making her a versatile and dangerous competitor in the Flyweight division.
Notable Events and Milestones
O’Neill’s UFC debut knockout and Performance of the Night award highlight her rapid rise. Her resilience through injuries and ability to compete at a high level across striking and grappling disciplines mark her as a notable athlete in women’s MMA.
Casey O’Neill Career Wins
Casey O’Neill has amassed a professional record of 10 wins and 2 losses, with victories achieved through knockouts, submissions, and decisions. Her diverse finishing ability underscores her well-rounded skill set.
UFC Highlights
O’Neill’s UFC tenure features several highlight wins, including a second-round knockout in her debut and a rear-naked choke submission against Lara Procópio. Her Performance of the Night award win against Antonina Shevchenko stands out as a career milestone. Despite recent setbacks, she remains a competitive presence in the Flyweight rankings.
Other Wins and Performances
Prior to joining the UFC, O’Neill secured multiple wins in regional promotions such as Eternal MMA and UAE Warriors. These performances established her as a promising talent and paved the way for her UFC contract.
Casey O’Neill Family
Family Background and Martial Arts Lineage
Casey O’Neill’s father, Cam, was a professional kickboxer, which significantly influenced her early introduction to martial arts. This family background provided her with early exposure to combat sports and a foundation for her fighting career.
Personal Life
O’Neill currently resides in Las Vegas, Nevada, USA. She has not publicly disclosed details about a spouse or children. Her focus remains on her professional fighting career.
2025 Season Performance
As of 2025, Casey O’Neill is ranked #11 in the UFC women’s Flyweight division. Training with Fight Ready, she aims to regain momentum following recent injuries and losses. Her performance outlook includes leveraging her striking and grappling skills to climb the rankings and contend for top positions in the division. Continued health and strategic fight selection will be critical for her success in the upcoming season.