He started out in customer service then transferred to QA and eventually worked his way up to game design.
Ellis remained with MicroProse for seven and half years, surviving two buy-outs (from Spectrum HoloByte and then Hasbro Interactive in 1999).
During this period, Ellis moved to the former MicroProse office in Chapel Hill, North Carolina to work as the designer of X-COM: Genesis.
He has written stories and scripts for games based on licenses from Cartoon Network (Adventure Time: Finn & Jake Investigations, Ben 10 Alien Force, and Ben 10 Omniverse), DreamWorks (Flushed Away, Madagascar 3 and Turbo), Universal (Despicable Me), Namco (Pac-Man and the Ghostly Adventures 1 and 2), and Warner Bros. (Yogi Bear).
Ellis holds a BSc from Towson University in Mass Communication (film and television production).