Marshall has a background in stop motion animation, and previously worked for years at Mackinnon & Saunders in Manchester, England, which made puppets for films and television commercials. He also worked at Jim Henson's Creature Shop, a company founded by puppeteer Jim Henson, creator of The Muppets.
Marshall was involved in the production of the Star Wars: The Clone Wars fifth-season episode Sabotage, making a clay model of Jedi Master Cin Drallig's head.
- The Art of Star Wars: The Clone Wars