He also starred in UPN's short-lived As If as well as recurring guest roles on Dawson's Creek and Dead Like Me.

Additionally, Dunne appeared in the made-for-television films Jewel, Au Pair II, Roughing It, Species III and Code Breakers.

Dunne also portrayed Robin Hood in the television film Beyond Sherwood Forest, directed by Peter DeLuise, starring alongside Erica Durance.

For this role, he was nominated for a Leo Award in the Best Lead Performance by a Male in a Dramatic Series category and won in 2010.

He returned to the show in 2014 in a recurring role as Mordecai, an Irathient lawyer and apparent reincarnation of an ancient astronaut of the same species.