Long was born the middle son of three boys in Fairfield, Connecticut, to father R. James Long, a philosophy and Latin professor at Fairfield University, and mother Wendy Lesniak, a former actress who has mostly appeared on stage. His paternal grandmother was of Sicilian descent. Long had a "kind of conservative" Roman Catholic upbringing. His older brother, Damian, is a local stage actor, teacher, and theatre director at Weston High School. Long attended Fairfield College Preparatory School, a Jesuit school, and Vassar College, where he was a member of the sketch comedy group Laughingstock and starred in several plays, including Butterflies Are Free.\n', '
Long\'s film credits include Idiocracy, Waiting..., Jeepers Creepers, DodgeBall: A True Underdog Story, The Break-Up, Crossroads, Galaxy Quest, Dreamland and Live Free or Die Hard. He was also a regular on the NBC TV series Ed (2000–04), playing socially awkward Warren P. Cheswick. He voiced the character of Alvin in Alvin and the Chipmunks, Alvin and the Chipmunks: The Squeakquel, Alvin and the Chipmunks: Chipwrecked, and Alvin and the Chipmunks: The Road Chip. He also played the main character in the comedy film Accepted (2006).\n', '
Long made a guest appearance in the documentary, Wild West Comedy Show (2006). In 2007, he co-starred with Bruce Willis as a "white-hat hacker" in Live Free or Die Hard and had a role in the comedy The Sasquatch Gang.\n', 'Long is known for his depiction of a Mac in Apple\'s "Get a Mac" campaign. The campaign featured commercials in which Long as a Mac and John Hodgman as a PC engaged in playful banter about "the strengths of the Mac platform and weaknesses of the PC platform."\n', '