A native of North Plainfield, New Jersey, he is best known for his voice roles of Dr. Drakken in Kim Possible, Bender Bending Rodriguez in Futurama, Wakka and Kimahri in Final Fantasy X, and Marcus Fenix in Gears of War. He is also known for Cory Halder on 6teen and Rico in the Madagascar franchise. He also voices Jake the Dog in Adventure Time. Additionally, he voiced Lava Mole on Breadwinners.
DiMaggio is a former stand-up comedian, appearing on stage as part of a comic duo named "Red Johnny and the Round Guy" and has several on-screen credits, such as Steve Ballmer in Pirates of Silicon Valley (the docudrama about the history of Apple Computer and Microsoft) and as Dr. Sean Underhill on Chicago Hope.