John O'Brien was born on April 1, 1966. He was a composer, known for The Break-Up (2006), Iron Man (2008) and Iron Man 2 (2010). He was married to Tierney. He died on August 20, 2011 in Chicago, Illinois, USA.
Found dead in his room in downtown Chicago's Millennium Knickerbocker Hotel, on Saturday, Aug. 20, 2011, by actor Peter Billingsley. Narcotics and sleeping pills were found in the room but an autopsy proved inconclusive.