Born in Houston, Texas, Mixon began his special make-up effects career working on local independent productions, including the 1984 thriller Courage, starring, co-written and produced by Ronny Cox. He eventually became a make-up lab technician and on-set makeup artist on more high profile productions, including The Nightmare on Elm Street Part 2: Freddy's Revenge (1985), The Supernaturals (1986, starring LeVar Burton and Nichelle Nichols), and The Texas Chainsaw Massacre 2 (1986). Perhaps more notably, he worked on 1984's The Terminator (featuring Dick Miller, Brian Thompson, and Paul Winfield) and was part of the "robot team" on the hit science-fiction action film, RoboCop, starring Peter Weller, Robert DoQui, Miguel Ferrer, Kurtwood Smith, Ray Wise, and the aforementioned Ronny Cox.