

O'Hara appeared in a number of Shakespearean productions, including Romeo and Juliet at the Regent Park Open-Air Theatre and The Comedy of Errors at The Pleasance. He went back to Scotland and landed a role in Bill Forsyth's Comfort and Joy, then returned to Central to finish his last term, where he was the understudy to Ralph Fiennes in A Midsummer Night's Dream. At age 17, he moved to London to study at the Royal Central School of Speech and Drama, but left after two terms because of a shortage of funds.

After leaving school he was accepted for a Youth Opportunities Programme, at a community theatre based at the Glasgow Arts Centre which toured local schools. His family was Catholic and of Irish descent. He lived with a large Catholic family, and was raised in the Pollok Housing Estate. O'Hara was born in Glasgow, Scotland, the son of Martha (née Scott) and Patrick O'Hara, a construction worker. Danny 'Mac' McGregor on The District, and Henry Howard, Earl of Surrey on The Tudors. X in Wanted, and Albert Runcorn in Harry Potter and the Deathly Hallows – Part 1. A graduate of the Royal Central School of Speech and Drama in London, he is best known to audiences for his numerous supporting roles in high-profile films including Irishman Stephen in Braveheart, dimwitted mobster Fitzy in The Departed, hitman Mr. David Patrick O'Hara (born 9 July 1965) is a Scottish stage and character actor.
