He started his career as director for Matt O'Callagahan's The Itsy Bitsy Spider. He first gained critical attention when he co-wrote, produced and directed the short film Herd, which won several film festival awards, including the Spirit of Slamdance Award at the 1999 Slamdance Festival. That same year, he made his feature film directorial debut with the comedy Deuce Bigalow: Male Gigolo, starring Rob Schneider. He later directed films like Surviving Christmas and Sky High. In 2006 he joined DreamWorks Animation and was a story artist for Shrek the Third and Creative Consultant for Kung Fu Panda. He also directed the movie Shrek Forever After and voiced the character Butterpants. He also worked as voice actor in Monsters vs. Aliens as additional voices. He also directed live action sequences on SpongeBob SquarePants. Mitchell will also direct Nightcrawlers, a supernatural action comedy.