Newton made his first grade début coming off the bench in Newcastle Knights 45–24 victory over New Zealand Warriors in Round 7 of the 2001 NRL season.

However it wasn't until Round 7 of the 2004 season that Newton held down a regular first team starting role after suffering two severe ankle injuries in 2003.

In 2006 he was selected to play Country Origin, but was ruled out with injury and replaced by the man he struck in the elbow late in the 2004 season, Ashton Sims (see below).

The next day, Newton announced he was leaving the Newcastle Knights after just 100 games, due to "personal reasons" and after learning coach, Brian Smith no longer saw him as a "must keep" for the remainder of the 2007 season or beyond.

[6] He started in the second row in the Storm's round 13 clash with the New Zealand Warriors in Auckland and was one of the best players on the field, playing the full 80 minutes.

[7] On 17 October 2007, he was released by the Melbourne Storm due to salary cap restrictions and announced his move to the Super League on a two-year contract at the Hull Kingston Rovers.

[8] Newton made his Hull KR début in the opening match of the 2008 season, a narrow 20–12 away defeat by reigning champions Leeds Rhinos.

Newton signed a two-year deal with the Penrith Panthers from 2012 having been brought in by Phil Gould to help rebuild the club, mentor younger players and use his experience to lead by example.