Rush Street was home to many music venues and while visiting the clubs Dunne decided to pursue an active career in show business.
He started playing piano in a back room of Lake Shore Park and joined one of the early 1970s comedy ensembles, The Conception Corporation.
[citation needed] Dunne also appeared in Chesty Anderson, USN (1976),[citation needed] the disaster spoof The Big Bus (1976),[2] Mel Brooks's High Anxiety (1977) as a lounge-room piano player,[2] three commercial parody films; Tunnel Vision (1976), American Raspberry (1977) and Loose Shoes (1980), and the teen comedy Bad Manners (aka: Growing Pains) (1984).
Later films include The Main Event (1979), The Last Married Couple in America (1980), Honky Tonk Freeway (1981), Perfect (1985), Hero and the Terror (1988), Phoenix (1998) and The Mothman Prophecies (2002).
He has also acted in numerous television shows including Night Court as well as working as a voice actor, and can be heard in Cowboy Bebop: The Movie, Ghost in the Shell: Standalone Complex and in the game, Star Trek: Klingon Academy.