Michael O'Brien



Tel: +1 416 617 0533


Bar Admissions: Ontario, 2013

Practice Areas:

  • Arbitration
  • Class Action Defence
    • Advertising & Consumer Claims
    • Appellate Litigation
    • Commercial Disputes
    • Competition & Anti-Trust Litigation
    • Defamation Claims
    • Directors & Officers Liability
    • Franchise Disputes
    • Leasing, Development & Management Disputes
    • Lobbying, Conflicts of Interest & Elections Finance
    • Professional Negligence
    • Public Interest & Constitutional Litigation
  • Employment Litigation
  • Investigations & Regulatory Defence
  • Medical Malpractice
  • Privacy & Technology Disputes
  • Shareholder, Partnership & Securities Disputes

Michael takes a practical and strategic approach to solving complex problems.

Michael is a partner at Tyr LLP. His litigation practice includes commercial and civil matters, private arbitrations, public inquiries, investigations and class actions. Michael represents publicly-traded and privately-held companies, directors, officers, shareholders and professionals in all manner of disputes, before courts, arbitral tribunals and regulators.

Michael represents emerging and established companies in various sectors, including consumer products, energy, financial services, infrastructure, manufacturing, real estate and technology. Clients value the tact and judgment that Michael brings to complex and sensitive matters, and consult Michael on their obligations in the political sector, including elections finance, conflicts of interest and lobbying law. Michael has considerable experience advising businesses and individuals, including public officials, responding to inquiries from regulatory bodies and legislative committees.

Michael represents both plaintiffs and defendants in class actions. He is the Vice-Chair of an American Bar Association subcommittee on Class and Derivative Actions, the former editor of the Class Action chapter of the ABA's annually published Recent Developments in Corporate and Business Litigation, co-author of its Cross-Border and Multijurisdictional Proceedings chapter, and a contributing author to the fourth and fifth editions of Defending Class Actions in Canada.

When representing plaintiffs in medical malpractice actions, Michael uses his years of experience litigating medical negligence claims to help clients navigate the complex medical malpractice landscape at their time of need.

Michael teaches the Corporate Remedies course for the Professional LLM Program at Osgoode Hall, York University, and is a faculty advisor for the Ryerson LPP Trial Advocacy Training Workshop.

Michael has been recognized by Benchmark Litigation as a Future Star and in its 40 & Under list, and by Lexpert Canada as a “Repeatedly Recommended” Corporate Commercial litigator. Prior to joining Tyr LLP in October 2019, Michael practiced commercial and civil litigation at McCarthy Tétrault LLP.

Click on a case to view details.

Aleafia Health Auditor Badesha v. Cronos Group Inc. Campaign Finance Advice Canadian Financial Institution re Data Breach Canadian Financial Institution re Injunctive Relief Canadian Financial Institution re Preparing Key Personnel Canadian Financial Institution re SASS Offerings Cannabis Company Chemical Supply Chain Master Distributor Commercial Warehouse Tenant Conflicts of Interest and Ethics Investigations Coxswain Row Capital Corporation v. Nigig Power Corporation et al. DCR Strategies Inc. v Gomez Defence of Energy Company in Abuse of Dominance Proceeding Delayed Diagnosis of Cancer - Failure to Diagnose Delayed Diagnosis of Tumour Director of Canadian Charity Franchisor Franchisor re Consumer Complaints Freshii Development, LLC et al. ats Kore Meals LLC Individual Plaintiffs Lobbying Investigations Professionals before Discipline Committee Professionals before Licensing Body Professional Defamation Shareholders in Well-Established Family-Owned Company STV Inc. Target of OSC Investigation Torstar
Community Involvement

Co-Founder & Co-Chair, The Charter Project, a public awareness and education initiative regarding the Canadian Charter of Rights and Freedoms

Board Memberships
  • Chair, Board of Directors, Camp Ekon, 2015-2019
  • Member, Board of Directors, Camp Ekon, 2013-2015
  • "Comparing Class Actions in Canada to those in the U.S." in Defending Class Actions in Canada: A Guide for Defendants, 5th Edition, LexisNexis, 2019. (chapter co-author)
  • "Cross-Border & Multijurisdiction Class Actions—A Canadian Perspective" in the American Bar Association's annually updated volume, Recent Developments in Business and Corporate Litigation (2014, 2015, 2017, 2018, 2019). (co-author and co-editor)
  • "Cross-Border & Multijurisdiction Class Actions—A Canadian Perspective" in Recent Developments in Business and Corporate Litigation: Class Action Law, 2016 Edition, American Bar Association, 2016. (co-author and co-editor)
  • "Multijurisdictional Issues" in Defending Class Actions: A Guide for Defendants, 4th Edition, LexisNexis, 2015. (chapter co-author)
Professional Affiliations
  • American Bar Association
  • Litigation Committee, Business Law Section
  • Vice-Chair, Sub-Committee on Class Actions, Business and Corporate
  • Canadian Bar Association
  • Ontario Bar Association
  • The Advocates' Society
Teaching Engagements
  • Since 2018, Michael has been a faculty advisor at the Ryerson LPP Trial Advocacy Training Workshop.
  • Michael is an instructor of the Corporate Remedies class for the Professional LLM program at Osgoode Hall, York University.
  • University of Windsor, JD, 2012
  • University of Waterloo, MA (English), 2010
  • University of Waterloo, BAH, 2007
  • 2023,  Benchmark Litigation, Future Star
  • 2023,  Benchmark Litigation, 40 & Under Hot List
  • 2022,  Benchmark Litigation, Shortlist—Emerging Talent Litigator of the Year
  • 2023,  Canadian Legal Lexpert Directory: Litigation—Corporate Commercial