O'Brien first played hurling to a high standard as a student at Ardscoil Rís in Limerick.
[1] O'Brien later lined out with the Mary Immaculate College freshers' team.
At club level, O'Brien first played hurling at juvenile and underage levels with the Kilmallock, before joining the club's senior team.
[2] He first appeared on the inter-county scene with Limerick during a two-year tenure with the minor team and won a Munster MHC medal in 2020.
[4] O'Brien was drafted onto the Limerick senior hurling team in 2023.