The Honourable Dennis O'Connor, O.C., O.Ont, K.C.

  • Phone No.: +1.416.848.0203
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Area of Practices:
Commercial contractual estate disputes financial valuation

The Honourable Dennis O’Connor, O.C., OOnt, K.C. Is the former Associate Chief Justice of Ontario from 2001 until his retirement from the Bench at the end of 2012. As a Member Arbitrator and Mediator, his practice focuses on commercial, financial, valuation, contractual, and estate disputes. He has been recognized by the Chambers Ranking Guide as one of Canada’s Most in Demand Arbitrators. 

The Honourable Dennis O’Connor, O.C., O.Ont, K.C. was appointed directly from the Bar to the Court of Appeal for Ontario in 1998.  He served as the Associate Chief Justice of Ontario from 2001 until his retirement from the Bench at the end of 2012.  While on the Bench, he sat on cases covering a wide range of commercial, civil, public, administrative and criminal matters.  In addition, he served as the Commissioner of two major public inquiries:  The Walkerton Inquiry (2000 – 2002) and the Maher Arar Inquiry (2004 – 2006).

Since leaving the Bench at the end of 2012, Mr. O’Connor has established a successful and busy arbitration and mediation practice.  His practice focuses on commercial, financial, valuation, contractual and estate disputes.  He is a member of Arbitration Place and a member of the Toronto Commercial Arbitration Society. Mr. O’Connor is recognized by the Chambers Ranking Guide as one of Canada’s Most in Demand Arbitrators, Band 1.

Before being appointed to the Court of Appeal, Mr. O’Connor was a senior litigation counsel at Borden & Elliot in Toronto for 18 years.  His practice involved commercial and public law issues.  He acted on many major cases in Ontario and elsewhere in Canada.  He also served as an elected Bencher of the Law Society of Upper Canada for 8 years.  After leaving the Bench, Mr. O’Connor returned to his former firm and is now Counsel in the Toronto office of Borden Ladner Gervais. 

Mr. O’Connor is an Officer of the Order of Canada and a Member of the Order of Ontario.  He has received several honourary degrees.  He was elected a fellow of the American College of Trial Lawyers in 1991.  He has also received a number of awards including the Advocates Society Medal, the Toronto Lawyers Award of Distinction, The Ontario Bar Association Award for Distinguished Service, the Canadian Civil Liberties Association Award for Excellence in Law. the Society of Ontario Adjudicators and Regulators Medal, The Canadian Water Resources Association Distinguished Achievement Award and the American Waterworks Association Award of Merit.

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