Comerford began his hurling career at junior club level with O'Loughlin Gaels. After a brief spell with the Brothers Pearse club in London, he returned to O'Loughlin Gaels and enjoyed his first success as a member of the 1996 Kilkenny Intermediate Championship-winning team and promotion to the top flight of Kilkenny hurling. Comerford later captained the club to the Leinster Club Championship in 2003 as well as two Kilkenny Senior Championships in 2001 and 2003. He made numerous championship appearances in three different grades of hurling for the club, while his early prowess also saw him selected for the Waterford Regional Technical College, with whom he won a Fitzgibbon Cup title..