 On 25 November 1990, O'Neill was just 16-years-old when he was a member of the extended panel of the Na Piarsaigh junior team that qualified to play Dromcollogher/Broadford in the Limerick Junior Championship final.He ended the game with a winners' medal following the 2-10 to 2-00 victory.On 3 October 1993, O'Neill was at full-forward when Na Piarsaigh faced Blackrock in the Limerick Intermediate Championship final.