Born in Los Angeles, California, he grew up playing sports, looking through telescopes, and being a professional magician (third-youngest member of the Magic Castle in 1976-77, as part of Dick and Diana Zimmerman's Young Magicians Program). He attended U.C. Berkeley to study astrophysics but left the program after two years, lingering in the Bay Area for two more years while writing his first novel, "Travail."

Returning to Santa Monica in 1981, Mark worked as a trainer at an upscale fitness center while trying his hand at short fiction and screenplays, some of which were optioned. He joined LFP, Inc. in 1983 writing short fiction, and rose to the rank of Senior Editor on several of their magazines. The job lasted seven months, until his first television work on the animated show "Challenge of the GoBots," which led to the rest of IMDb.