O'Connor attended De La Salle College and Osgoode Hall Law School of York University in Toronto.
From 1976 to 1980 he became a teacher at the University of Western Ontario Faculty of Law and from there went to practise litigation at Borden, Elliot in Toronto.
He was a negotiator for the Government of Canada in the Yukon land claim debate.
On August 12, 2013, Toronto police chief Bill Blair announced that he had requested O'Connor conduct an internal review into the use of force by police.
[1] On June 30, 2016, O'Connor was made an Officer of the Order of Canada by Governor General David Johnston for "his service to the legal profession and for his commitment to justice as a commissioner of the Walkerton and Arar inquiries.