[2][3] Thomson had a number of television roles in New Zealand, starting with Marlin Bay, a drama set in a casino and resort.

In 1995, Thomson moved to Australia and landed regular roles in Pacific Drive, medical series All Saints (1999–2003) and The Alice (2005).

He appeared in Somersault with Abbie Cornish and Sam Worthington, which scored him an AFI Award.

He also featured in Accidents Happen with Geena Davis and Storm Boy with Geoffrey Rush, and Finn Little.

[9] Thomson won an Australian Film Institute Award for Best Actor in a Supporting Role for his performance in Somersault, and was nominated for his work in The Black Balloon.