Gary started out his playing days with Stella Maris in Dublin before heading across the water to join Middlesborough where he played alongside Sean Prunty during his time there. He returned home to play with St. Patrick's Athletic for a brief period before signing for Drogheda United, where he played for six seasons, winning the First Division League title in the 2001/02 season.

In 2005 Gary joined Longford Town but moved on to Bray Wanderers at the end of the 2006 season. He spent three seasons at Bray before returning to Longford at the start of the 2010 season. Over the next three seasons at Flancare Park Gary made 52 appearances for Longdford. He retired and became the assitant manager of Longford Town, working alongside Tony Cousins