He was the head coach of Manawatu's provincial rugby union side in New Zealand. He has previously been the head coach of rugby union Top League side, the Kubota Spears. O'Halloran had played 95 games and scored 35 tries for Wellington between 1993 and 2001 and 54 games with 17 tries for the Hurricanes at Super 12 level from the inaugural 1996 season. He was also often the Wellington and Hurricanes captain. He had international experience as well after he received his first and only All Black cap when he went on for the final few minutes of the international against Italian team late in the 2000 season.