- Narrates the short story "Everything's Eventual" on the audio book of the same name. The book is a collection of short stories written by Stephen King. Oliver Platt and others narrate as well.
- TV commercial for Pepsi Vanilla, 2003.
- Has also experienced success on the stage in New York. The plays he's appeared in include "The Hot L Baltimore," "The Shadowbox," "Final Exam," and "Barefoot in Athens."
- TV commercials for Apple Computer (Get a Mac) with John Hodgman (2006).
- Justin plays "Mac", an Apple computer in several commercials.
- Narrator of Then again, Maybe I Won't by Judy Blume 2002