Drafted by the Kangaroos in the fourth round of the 2006 AFL Draft from the Port Adelaide Magpies, Thomas made impressive performance by kicking four goals in his first pre-season game against Collingwood in the NAB Cup at Carrara Oval.

Thomas made his AFL debut in Round 1 of the 2007 season, scoring no goals but five behinds in a loss against Collingwood.

In 2010 Thomas led North Melbourne's goalkicking with 29 goals which included 7 against Carlton in Round 12.

He also finished seventh in the Coleman Medal, the highest position for a small forward that year.

[4][5] Thomas made his debut for Port Adelaide in round 5 of the 2018 season, kicking one goal in a 34 point loss to Geelong.