*Club domestic league appearances and goals, correct as of 20:32, 4 January 2025 (UTC) ‡ National team caps and goals, correct as of 23:50, 27 September 2022 (UTC)
In September 2019, O'Connor joined Celtic, signing a four-year contract until 2023.[6][7]
Partick Thistle loan
In January 2020, O'Connor joined Scottish Championship club Partick Thistle on loan, joining Ian McCall's side for the second half of the season.[8] He made his debut in senior club football on 25 January 2020, in a 2–1 loss to Arbroath.[9] He made five appearances in all competitions for the club before the season was ended prematurely due to the COVID-19 pandemic.[10]
Tranmere Rovers
O'Connor joined League Two club Tranmere Rovers on 17 August 2020 on a season-long loan.[11] He made 42 appearances over the course of the season and returned to Celtic for pre-season.[12] O'Connor returned to Tranmere Rovers on another season long loan on transfer deadline day, 31 August 2021.[13] The transfer was made permanent in January 2022.[14]