Education

Harrington began his education at St. Margaret of Cortona for elementary school and continued on to Fordham Preparatory School for high school. Academics did not come easily to him, and he found formal education challenging. He briefly attended Manhattan College but left after six weeks, deciding not to pursue a degree.

Early Career and Entry into Acting

Following his departure from college, Harrington explored various jobs including manual labor, cold-calling for a brokerage firm, landscaping, and bartending in Manhattan. It was during his time as a bartender that a coworker recommended he try acting classes—a suggestion that would shape the path of his professional life.

After taking acting classes, Harrington secured his first film role in Luc Besson's historical drama The Messenger: The Story of Joan of Arc (1999), where he portrayed Aulon. His performance opened the door to further opportunities in television and film.

Breakthrough Roles in Film and Television

Harrington appeared in a variety of film projects early in his career, including Boiler Room as a trainee at JT Marlin, Drop Back Ten as Spanks Voley, Massholes as Bing, Riding in Cars with Boys as Bobby, My First Mister as Randy, and The Hole as Mike Steel—a role that gained him notable attention. He also appeared in the psychological thriller Ghost Ship and the horror film Wrong Turn, both of which contributed significantly to his rising profile.

On television, Harrington gained widespread recognition for his recurring role as Jesse Keys—an alien abductee—in Steven Spielberg's science fiction miniseries Taken. In 2007, he made a guest appearance on Law & Order: Criminal Intent as a serial killer, showcasing his range as an actor.