Born and raised in West Bloomfield, Michigan, just outside of Detroit, Justin Bartha trained at New York University's Tisch School of the Arts. Justin Bartha made his motion picture debut as Brian, the psychologically-challenged younger brother of a powerful federal prosecutor in Gigli (2003), opposite Ben Affleck, Jennifer Lopez and Christopher Walker. His next feature film role was as Riley Poole in National Treasure (2004) opposite Nicolas Cage. Bartha reprised the role in the sequel, National Treasure: Book of Secrets (2007).
Following roles in Trust the Man (2006) with David Duchovny and Failure to Launch (2006) starring Matthew McConaughey and Sarah Jessica Parker, Bartha took on a lead role as the main character in the NBC mid-season comedy Teachers (2006). Unfortunately, the show didn't last long, but Bartha bounced back with a number of roles in major motion pictures such as National Treasure: Book of Secrets (2007)and The Hangover (2009).