Denis, who has a PhD in Theoretical Chemistry, has appeared on such television shows as The Golden Girls, Newhart, and Perfect Strangers. A 1989 episode of Growing Pains had him playing a director on a television show on which a crewmember played by Carlos LaCamara worked. That same year, Denis appeared in two episodes of Just the Ten of Us, including one episode with Bill Erwin. In 1990, Denis guest-starred in an episode of the short-lived Gabriel's Fire, starring Madge Sinclair and also guest-starring Jack Kehler.