O'Connor was born in Southampton, Hampshire, England. He is a grandson of the British sculptor John Bunting. His maternal aunt is British writer and commentator Madeleine Bunting. His ancestry is Irish, English, Scottish and, through his matrilineal great-grandmother, Ashkenazi and Sephardi Jewish.
He trained at the Bristol Old Vic Theatre School, from which he graduated in 2011.O'Connor is a Southampton FC supporter.
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