David O'Hara was born in Glasgow, Scotland, to Patrick and Martha O'Hara. After leaving school he was accepted for a Youth Opportunities Programme, at a community theatre based at the Glasgow Arts Centre. It toured local schools under the direction of Robin Peoples.David moved to London at age 17 to study at the Central School of Speech and Drama but left after two terms because of a shortage of funds. 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. He was understudy to Ralph Fiennes in "A Midsummer Night's Dream."He performed in "Romeo and Juliet" as Tybalt, directed by Declan Donnallan for the New Shakespeare Company, at the Open Air Theatre in London's Regent Park, which was followed by a European tour. Other theatre credits include "The Comedy of Errors" at the Pleasance Theatre, Edinburgh, Scotland, and "Aff the Other Man" at the Haymarket. He spent a year at the Royal Shakespeare Company at Stratfor