O'Neill first played hurling to a high standard as a secondary school student at Doon CBS.
[2][3] O'Neill later played with Cork Institute of Technology in the Fitzgibbon Cup.
[5] By that stage, O'Neill had progressed to adult level with Cappawhite and won three West Tipperary SHC titles between 2000 and 2005.
[6][7] O'Neill first appeared on the inter-county scene with Tipperary at minor level.
[10] He was at full-forward when Tipperary were beaten by Clare in the 1997 All-Ireland final, however, he ended his debut season by being named Young Hurler of the Year.