Williams was a Marist Saints junior[18] when he was spotted playing in Auckland by Bulldogs talent scout John Ackland. In 2002 he was offered a contract and moved to Sydney (as the youngest player to ever sign with an NRL club)[19][20] to play in the Bulldogs junior grades.[21] While training professionally he also worked full-time as a labourer.[22] He advanced up the ranks quickly, becoming a starting player in the forward pack for the Bulldogs Jersey Flegg Cup side in his first year. The following year Williams cemented a starting spot in the Premier League side