John Mather is a partner at DMG Advocates practicing commercial and public litigation.

John is an experienced advocate who regularly appears before the Ontario Superior Court and Court of Appeal. He has also acted in numerous domestic and international arbitrations, including in New York and Riyadh, Saudi Arabia.

From 2019-2020, John served as Associate Commission Counsel to former Associate Chief Justice Frank Marrocco on the Collingwood Judicial Inquiry, a large public inquiry examining two major transactions undertaken by the Town of Collingwood.

John has broad experience in matters involving:

  • Product liability
  • Procurement (public and private)
  • Contractual disputes
  • Commercial leasing, condominium and real estate disputes
  • Urgent proceedings and injunctions
  • Municipal law and governance
  • Administrative and regulatory proceedings
  • Corporate governance
  • Defamation law
  • Constitutional law

John’s clients have included leading automobile manufacturers, condominium boards, telecommunications providers, newspaper publishers, oil and petrochemical producers, steel manufacturers, professional service firms and restaurant franchisors, as well as government agencies, and non-profit organizations.

Prior to joining DMG Advocates in 2018, John spent five years as an associate lawyer at a leading national firm.

John earned his law degree from Western University, where he graduated with Distinction. Prior to law, John worked as a journalist in Canada and the United Arab Emirates.

Bar Admission

  • Ontario (2013)


  • Juris Doctor (with Distinction), Western University (2012)
  • Bachelor of Journalism (Honours), Ryerson University (2007)
  • The Advocates’ Society
  • Ontario Bar Association
  • Toronto Lawyers Association