John E. Callaghan

John Callaghan is a partner in Gowling WLG's Toronto office with a broad practice in civil and commercial litigation and regulatory offence work. He is a past leader of the firm's Commercial Litigation Group.

John has acted on an array of different matters. He regularly acts for large corporations, financial institutions and government and regulated industries. He has appeared at both the trial and appellate level, and has reported cases in such areas as contract, environmental law, elections law, corporate, competition, constitutional, statutory interpretation and class actions. He has acted on several public inquires, including the Walkerton Inquiry and the Cornwall Inquiry.

John has been recognized by several publications as a leading commercial counsel in Canada, including Lexpert/American Lawyer Guide to the Leading 500 lawyers in Canada; Lexpert/American Lawyer Guide to The Leading 500 Cross-Border Lawyers in Canada; Benchmark Canada: The Definitive Guide to Canada's Leading Litigation Firms and Attorneys; the Best Lawyers in Canada and Financier Worldwide Litigation and Adjudicator Resolution Handbook.

John was elected a Bencher by the legal profession in Ontario through the Law Society of Upper Canada, the governing body of lawyers in Ontario. In his capacity as a Bencher, John adjudicates professional misconduct allegations against lawyers. At the Law Society, John is currently the Vice-Chair of the Audit and Finance Committee and is Vice-Chair of Government Relations.

John is the second-longest-serving member of the Civil Rules Committee in Ontario, having been appointed by successive Chief Justices of the Ontario Superior Court of Justice. The Rules Committee is responsible for drafting and revising the Rules of Civil Procedure for the Province of Ontario. In this capacity, John has conducted numerous reviews regarding the civil justice system, and has been involved in most of the major procedural reforms in Ontario over this last two decades.

John is co-author of Class Actions: Law and Practice (Lexis/Nexis). The text is the leading authority on the subject of class actions in Canada and has been frequently cited with approval by the Supreme Court of Canada and other appellate and trial courts across Canada.

John is a frequent lecturer on issues of procedure and trial advocacy. He has chaired several of the leading class action conferences in Ontario. He has also spent a number of years as an instructor of trial advocacy with the Faculty of Law at the University of Toronto.

Involvement in the legal profession

  • Vice Chair, Law Society of Upper Canada, Audit and Finance
  • Vice-Chair, Law Society of Upper Canada, Government Relations
  • The Advocates' Society, Director (2007-2009)
  • Chair, The Advocates' Society - International Conferences to The Hague (2004) and Ireland (2006)
  • Adjunct Professor, University of Toronto Faculty of Law, Trial Advocacy (1996-2000)
  • Rules Committee (1995-present)
  • Chair, Simplified Rules Review Committee (1995-1998)
  • Chair, Cost Review Committee (2002-2004)
  • Chair, Appellate Delay Committee (1996)
  • Member, Civil Procedure Reform Implementation Committee (2010)
  • Director, Institute of Clinical and Evaluative Studies (2007-2013)
  • Fox Scholar (1989-90)
  • Class Action Editor, Toronto Law Journal
  • Hockey coach - best job of all!

Career & Recognition

Filter timeline:


  • Bencher, Law Society of Upper Canada
  • Fellow of the American Bar Foundation
  • Founding Director of the Institute of Civility and Professionalism

John is the co-author of Class Actions Law and Practice 2nd Edition, LexisNexis Canada, 2008

John has chaired and spoken at numerous conferences, particularly on Class Actions. He has written several articles for the CBA, ABA and other institutions

Insights & Resources