He appeared as Claus Van Zandt in 1985 on the soap opera Days of Our Lives, and as Leo Mitchell in 1989 on Santa Barbara. He has also made guest appearances on many other TV series, including Battlestar Galactica (original series), V, Babylon 5, Queen of Swords, and MacGyver. De Longis provided his voice in a Star Trek video game. De Longis was the voice actor as the main antagonist Lord Zygon in Starchaser: The Legend of Orin on 1985 film.