From 1970 to 1974, Lewis was a commercial film director for J Leslie & Associates, directing over 100 television commercials.

Lewis loved Warren's horror magazines and submitted an unsolicited story. Bill Dubay chose him as lead writer and he produced 200 stories (1974-1982) for Creepy, Eerie, Vampirella and The Rook (which he co-created).

During his later years at Warren, Lewis also worked as as storyboard director–special effects for New World Pictures (1979-1980) and storyboard/conceptual artist for Universal (1981-1983). When Warren folded, he moved to California and secured work initially with Roger Corman's films. Burnt out from writing, for 20 years he worked in animation, film design and special effects.

Lewis was involved with films such as Terminator (1984), R.O.T.O.R. (1987), Dark Angel (1990) and Dragonfight (1990). Lewis distanced himself from R.O.T.O.R., arguing his script had been ruined. He worked for many animated television shows until 1997, including The Smurfs (1987), The Care Bears Family (1985), The Real Ghostbusters (1991) and The Incredible Hulk (1996).

As movie and animation work stalled in Los Angeles, Lewis worked as creative director for Spunky Productions in 1999-2000 doing Internet animation for kids, co-creating scary.com and claus.com. He pursued freelance writing projects and worked on The Red Queen Codex and X-Isle for Lightstorm Entertainment (James Cameron).

Lewis and his wife Grae moved to Oregon and then temporarily to Vancouver BC so Grae could retrain as a publisher. With co-creator of The Rook, Bill DuBay, Lewis formed Time Castle Books in 2008 to republish their creation. DuBay was soon diagnosed with cancer and health problems stalled the project. Lewis lost his home and savings due to the 2008 global financial crisis and received help from The Hero Initiative.

In 2010, the Lewises were running a Japanese-fusion hot dog cart (Domo Dogs) in Portland. To fund the venture, Lewis sold his rights to The Rook.