He has made several appearances as Army Sergeant Dixon on the TV series Dr. Quinn, Medicine Woman. That show's regular cast members includes Barbara Babcock. De Zarn has also appeared in an episode of Quantum Leap, starring Scott Bakula and Dean Stockwell, and an episode of 7th Heaven, starring Catherine Hicks and Stephen Collins.
His motion picture credits include Tales from the Crypt Presents: Demon Knight (1995, with William Sadler, Dick Miller, John Schuck, and John Larroquette, Fight Club (1999, with David Andrews), and Spider-Man (2002, with Kirsten Dunst).
- TNG: "Starship Mine" as Satler
- DS9: "Wrongs Darker Than Death or Night" as Halb