He started as a coach at St. Helens before joining Huddersfield Giants as an assistant coach in 2005.[8] At Huddersfield, he worked under head coach Jon Sharp, who rated him as one of the best young coaches in the game. Following Sharp's departure from the club in 2008, Purtill had a brief spell as caretaker coach alongside Paul Anderson. He then moved to St Helens where he worked under Michael Potter and then Royce Simmons. He also became head coach of the Canada Wolverines rugby league team and in 2011 the England Knights team. He also did a PG Dip in Elite Coaching Practice at the University of Central Lancashire. He parted company with St Helens along with Royce Simmons on 18 March 2012 following a run of 5 games without a win. He has since been linked with a return to Huddersfield or to Bradford Bulls, both in assistant roles.