In the 1970s, 1980s and 1990s, he appeared in Barnaby Jones, Cannon, Gunsmoke, Married With Children, E/R, Highway to Heaven, Who's The Boss?, Growing Pains, Full House, The Golden Girls, Moonlighting, and Star Trek: The Next Generation. In Star Trek: The Next Generation, Erwin played Dr. Dalen Quaice, a friend and mentor of Dr. Beverly Crusher. He was the first character to disappear in the episode "Remember Me".