O'Reilly played hurling at all grades during his time as a student at Coláiste Mhuire in Thurles. He was part of the school team that won the Munster PPS U17HC title in 2023, following a one-point win over Hazelwood College.[1] At club level, O'Reilly first played for Holycross–Ballycahill at juvenile and underage levels and won a Tipperary MAHC medal in 2022.[2]
At inter-county level with Tipperary, O'Reilly captained the minor team to the All-Ireland MHC title, following an extra time 2–17 to 3–12 win over Kilkenny in the final.[3][4] He was later named on the Minor Team of the Year.[5] O'Reilly immediately progressed to the under-20 team and won an All-Ireland U20HC medal in 2025.[6]
O'Reilly was added to the senior team in 2026.[7] He made his debut against Galway in the 2026 National Hurling League.[8]
- As of 1 February 2026