Not much is known about Hasler's life. He appeared as T-Shirt in the children's TV series T-Bag from 1985–92.
Hasler has appeared in Renford Rejects and Casualty and provided voices and automated dialogue replacement (ADR) for a number of TV, radio and film productions.
In 2012, Hasler joined the voice cast of Fireman Sam as James Jones, taking over the role from Steven Kynman and Arnold McKinley.
Gallery of photographic stills used to promote the actor.