Was ranked #25 on Entertainment Weekly's '30 Under 30' the actors list. (2008).

His senior year at Fairfield Prep, Justin received the "Most likely not to be seen in class" superlative.

Attended Vassar College in Poughkeepsie, New York.

He was in the movie The Break-Up (2006), which premiered on his birthday.

Has been noted for his resemblance to Tim Allen, who was his co-star in Galaxy Quest (1999).

After graduating from Fairfield Prep (Fairfield College Preparatory School), he attended Vassar College, where he was in the graduating class of 2000. He was a member of "LaughingStock," a sketch comedy group at Vassar. He appeared in two independent films, "Boygazm!" and "Time Writer," before appearing in his first commercial film, Galaxy Quest (1999).

His father, R. James Long, teaches philosophy at Fairfield University.

His mother Wendy - a stage actress - teaches at Roger Ludlowe Middle School, in Fairfield, Connecticut.

Has an older brother, Damien Long, and a younger brother, Christian Long, both of whom are actors. Has one dog named, Moose.