The Honourable Mr. Justice Warren K. Winkler is Chief Justice of Ontario. He was a founding partner of one of Canada’s leading management-side labour firms, Winkler, Filion & Wakely, where he practised in the fields of labour and employment law, and administrative law. Since his appointment to the bench in 1993, Mr. Justice Winkler has made his mark in the development of class action jurisprudence, while at the same time resolving a number of high-profile multi-party disputes, including the dispute between Ontario Hydro and the Power Workers' Union, and the restructuring of Air Canada, where he successfully mediated a deal between the company and key unions in order to keep the airline in business.

He received his B.A. from University of Manitoba and his LL.B., LL.M. from Osgoode Hall Law School. In April 2006 he was awarded the University of Toronto's Bora Laskin Award for outstanding contributions to labour law. He was appointed Chief Justice of Ontario in June 2007.