Prior to his Star Trek appearance, he guest starred in the television series Pacific Blue (1998, episode House Party, alongside Mark L. Taylor) and Touched by an Angel (1998, episode What Are Friends For?, with Erich Anderson and Wren T. Brown) and played Paul in the first season of MTV's Undressed (1999, with Christopher Pettiet, Bahni Turpin, Todd Babcock, and Corey Mendell Parker). Karrer has studied for five years at the Ivana Chubbuck Studios and has written and directed a few short films, including It's Like Horse Racing and The Late Bloomer.