O'Hara began acting at age ten, appearing in school plays including a local production of The Nutcracker where she played Clara. She is the youngest of two siblings. At 17, O'Hara moved to New York City to attend The New York Conservatory For Dramatic Arts. In 2006, O'Hara was cast as a lead in the New York debut of the recently discovered Tennessee Williams' play Pieces of Paradise, directed by Stephan Morrow.