In 1995, he played Father Paul in Her Hidden Truth. In 2007 Clapp voiced Horny The Clown in the horror film Drive-Thru. Clapp portrayed a corrupt police officer in a 2008 episode of Cold Case. He played the main antagonist Gen. Peter Randall in the Prototype video game. Clapp plays the father of Ellen (Rose Byrne) in the F/X show Damages.