 Dominating in 2010 and 2011, O'Hanlon in 2010 was named on the bench to play first grade against the New Zealand Warriors in round 17, but did not play.O'Hanlon made his NRL debut in round 17, 2011 against the Brisbane Broncos, coming off the bench to play centre for the injured Jacob Loko.O'Hanlon played nine games in his debut season for Parramatta as the club narrowly avoided the wooden spoon.