Gary O'Neill

UCD O'Neill returned to Ireland in February 2015, signing with UCD where manager Pat Devlin was a friend of his father. He was named on the PFAI Team of the Year for 2015, alongside teammates Thomas Boyle, Robbie Benson, and Ryan Swan. UCD secured promotion that season as champions of the First Division.

Shamrock Rovers In June 2019, O'Neill signed with Shamrock Rovers. Manager Stephen Bradley expressed his delight at the acquisition, highlighting O'Neill's fit within the team's playing style and his potential for further development. On 3 November 2019, he scored the winning penalty in the 2019 FAI Cup final in a shootout victory over Dundalk at the Aviva Stadium. He was an unused substitute in the 2021 President of Ireland's Cup final defeat to Dundalk. He did manage to play in the 2022 President of Ireland's Cup, which finished as a 1–1 draw, and converted his penalty in the 5–4 shootout victory. He went on to feature as a half-time substitution the 2024 President of Ireland's Cup, a 3–1 victory over St Patrick's Athletic. He missed 11 games of the 2024 campaign due to injury. He was not in the matchday squad for the 2025 FAI Cup final win over Cork City following a cancer diagnosis, but recorded a video message of support for his teammates in the run up to the game.

Style of play O'Neill is renowned for his exceptional passing ability, boasting a passing accuracy above 90%. In 2019, he was the only player to complete over 2,000 passes in the season, averaging 71 completed passes per game, accounting for 13% of Shamrock Rovers' total passes.

Personal life In April 2026, O'Neill revealed that he had been diagnosed with testicular cancer in October 2025 and had undergone chemotherapy treatment, with the treatment and recovery period keeping him out of action for a long-term period.

Career statistics + Appearances and goals by club, season and competition

Division!!Apps!!Goals!!Apps!!Goals!!Apps!!Goals!!Apps!!Goals!!Apps!!Goals!!Apps!!Goals Port Vale 2013–14 League One

Southport (loan) 2013–14 Conference

Hereford United 2014–15 Southern LeaguePremier Division

2015