Mark began acting in high school and got his first professional acting job just after graduating, with a summer melodrama theatre in the Minneapolis area. This was followed by four years at the University of Minnesota, getting his degree as a theatre major.After teaching junior high school for a year, and another year of travel in Europe, he was accepted to the Ringling Bros. and Barnum & Bailey Clown College, and performed as a clown in their 1972 season. Following this, Mark moved to New York to pursue an acting career, and performed in a couple of unsuccessful Off-Broadway shows and a Broadway-bound musical, which closed to bad reviews in previews. He moved to Los Angeles in 1974, where his general theatre background and circus connections helped get him interesting odd jobs while pursuing work as an actor. He was hired as a sculptor for a new monster make-up show, "The Land of A Thousand Faces", at Universal Studios Tour. He got to know the special make-up effects community, which led directly to his role in "The Crater Lake Monster", for which one of his friends was building the monster. Although he was cast in a few small roles in TV, industrial films, and commercials, his acting career never took off. But his work as a sculptor did, and after three years at Universal, he began freelancing as a creature-maker, eventually working on major films. In 1988, he moved to the San Francisco area, where he currently works as a sculptor/creature-maker/puppeteer for George Lucas's Industrial Light and Magic.