Na Piarsaigh qualified for a second successive Limerick Intermediate Championship final on 6 November 1994, with Tournafulla providing the opposition.
[3] O'Neill was called up for a trial with the Limerick minor team prior to the start of the 1991 season, however, he failed to make the championship panel.
Again eligible for the grade the following year, he was an unused substitute on 22 April 1992 when Limerick suffered a 1-07 to 0-09 defeat by Tipperary in the Munster Championship.
O'Neill made his championship debut on 18 June 1995 when he came on as a 62nd-minute substitute for Pat Heffernan in a 0-16 to 0-15 defeat of Tipperary in the Munster semi-final.
O'Neill was dropped from the starting fifteen for the replay a week later but collected a Munster Championship medal as an unused substitute after a 4-07 to 0-16 victory.
In April 2014, it was confirmed that O'Neill had replaced Seán Stack as manager of the Na Piarsaigh senior team.
[7] His debut championship campaign saw Na Piarsaigh remain undefeated in the group stage and qualify for the final against Kilmallock on 19 October 2014 where his side suffered a 1-15 to 0-14 defeat.
[16][17] On 2 September 2021, after two years in charge, O'Neill announced that he would not be seeking an extension to his term as Galway manager and would leave the position.