Before defecting to the professional code of rugby league, Halligan played amateur rugby union for Waikato. In rugby league Halligan was renowned as a fine goalkicker, his 855 first grade goals coming at an impressive 80% success rate.
He also taught Johnathan Thurston how to kick conversions. It was said at an interview that Halligan taught Thurston whilst he was at Sydney club the Canterbury-Bankstown Bulldogs. Also that Halligan hated the way Thurston "hooks" the ball. Halligan taught Thurston to control the hook so it comes in or goes out.