While in college at Coastal Carolina University, he studied law and took an elective acting course. Kelly's debut TV performance came in 1994 on HBO's A Body to Die For: The Aaron Henry Story. He went on to portray Michael Kaufman in the 1999 release of Man on the Moon. The next year, Kelly appeared along with big hitters such as Robin Wright Penn, Bruce Willis and Samuel L. Jackson in the movie Unbreakable. He also had several appearances in the TV series Fringe, along with a starring spot in the spin-off series Criminal Minds: Suspect Behavior. The independent film Loggerheads, in which Michael portrayed the character George, received a nomination for the Grand Jury Prize - Dramatic at the 2005 Sundance Film Festival. Kelly also costarred in the 2009 comedy, Did You Hear about the Morgans? with Sex in the City star Sarah Jessica Parker, and Hugh Grant.