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John Polyzogopoulos

Partner
jpolyzogopoulos@blaney.com
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P: 416-593-2953
F: 416-594-5083
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Practice Areas Call to the Bar Education Assistant

Practice Areas

Call To The Bar

  • Called to the Bar of Ontario, 2000

Education

  • LL.B., Osgoode Hall Law School, 1998
  • B.A., Economics, University of Toronto, 1995

Assistant

Sumaya Intriago
Linkedin
John Polyzogopoulos Photo ©2026 Blaney McMurtry LLP
 Overview

John is a Toronto-based commercial litigation lawyer who represents businesses, shareholders, professionals and individuals in complex corporate, estate and sports-related disputes across Ontario. His practice focuses on shareholder and partnership disputes, breach of contract claims, estate litigation between beneficiaries and trustees, and insolvency matters including bankruptcy and receivership proceedings.

John regularly appears before the Ontario Superior Court of Justice, the Ontario Court of Appeal and arbitration tribunals, assisting clients in resolving disputes through litigation, mediation, arbitration and negotiated settlements.

In September 2024, John was appointed Practice Group Leader of the firm’s Commercial Litigation Group.

Commercial and Corporate Litigation

John advises clients on a wide range of corporate and commercial disputes, including:

  • Shareholder and partnership disputes
  • Breach of contract claims
  • Franchise disputes
  • Commercial tenancy disputes
  • Construction disputes
  • Real estate litigation
  • Debt collection litigation
  • Product liability claims
  • Environmental contamination disputes
  • Bankruptcy and receivership proceedings

He regularly represents businesses and professionals involved in complex commercial litigation across Ontario.

Estate Litigation

John acts for beneficiaries, executors and estate trustees in estate-related disputes, including:

  • Will challenges
  • Beneficiary disputes
  • Executor and estate trustee disputes
  • Estate administration conflicts
Sports Law and Governance

John represents amateur hockey organizations and other sports bodies at the local and national levels, as well as athletes involved in governance and disciplinary matters. His work in this area includes:

  • Governance disputes within sports organizations
  • Internal disciplinary proceedings
  • Athlete representation in dispute resolution processes
Appeals and Complex Litigation

John also assists clients with civil appeals and complex procedural matters. His work includes:

  • Appeals before the Ontario Court of Appeal and other appellate courts
  • Professional negligence claims involving accountants, lawyers, engineers, real estate agents and financial advisors
  • Defamation and Privacy Litigation
  • Civil fraud matters
  • Enforcement of foreign judgments and jurisdictional disputes
  • Injunctions and extraordinary remedies
Courts and Tribunals

John has appeared before:

  • Supreme Court of Canada
  • Ontario Court of Appeal
  • Ontario Divisional Court
  • Ontario Superior Court of Justice
  • Nunavut Court of Justice
  • Administrative tribunals
  • Private arbitration panels
Thought Leadership

John is the editor of the firm’s litigation blog Blaneys Appeals, which provides weekly summaries of civil decisions released by the Court of Appeal for Ontario. The blog receives thousands of monthly readers and is distributed widely through legal information platforms including Mondaq, Lexology, CanLII and the Ontario Bar Association.

John also co-authored two chapters in Civil Procedure and Practice in Ontario (2nd ed.), an annotated version of Ontario’s Rules of Civil Procedure published by the Canadian Legal Information Institute (CanLII).

He also edits the firm’s Commercial Litigation Update newsletter.

Recognition

John was recognized by Best Lawyers® in Canada in 2024 and 2025 in the area of Corporate and Commercial Litigation.

 Education
  • LL.B., Osgoode Hall Law School, 1998
  • B.A., Economics, University of Toronto, 1995
 Practice Areas
 Called to the Bar
  • Called to the Bar of Ontario, 2000
 Assistant
Sumaya Intriago
 Experience
  • BDAR v ITSO 2025 , Barrie & District Association of Realtors v. Information Technology of Systems Ontario et al., 2025 ONSC 3388 -

    View decision here and here.
  • Anson Advisors Inc. et al v. Doxtator et al, 2024 ONSC 437, 2024 ONSC 977 (CanLII) -

    Successfully had half a million default judgment set aside and obtained almost $80,000 costs award in multi-million dollar defamation and conspiracy case. View decisions here: 2024 ONSC 437, 2024 ONSC 977
  • HK United Construction Ltd. v. Malanca, 2022 ONSC 6295 (CanLII) -

    Successfully imposed on registered owner a notice obligation and security over proceeds of sale of a valuable commercial property pending the court’s determination of the extent of our client’s interest in the property. View decision here.
  • Royal J&M Distributing Inc. v. Kimpex Inc., 2021 ONSC 3777 (CanLII) -

    Representing client in defence of breach of contract and civil conspiracy claim involving alleged contraventions of the price maintenance provisions of the Competition Act. View decision here.
  • Susan Eng v. Elizabeth Eng, 2021 ONSC 464 (CanLII) -

    Acted for client in dispute over the validity of the appointment of a litigation guardian of an elderly plaintiff. View decision here.
  • Eastern Financial Mortage Corp. v. Athanasoulis, 2020 ONSC 7815 (CanLII) -

    Acted for client in defence of claim made under a guarantee and in effort to have matter heard in foreign jurisdiction rather than Ontario. View decision here.
  • Chaitas v. Greasley, 2019 ONSC 1158 (CanLII) -

    Assisted client in compelling the sale of co-owned investment properties and obtaining a costs award. View decision here.
  • 2212886 Ontario Inc. v Obsidian Group Inc., 2016 ONSC 6836 (CanLII) -

    On behalf of a franchisor client, succeeded in obtaining permission from the court to file a late affidavit in defence of a motion for summary judgment which ended up proving critical to the client ultimately succeeding in resisting the plaintiff’s motion for summary judgment on appeal. View decision here.
  • Kassiouris v Kalantzis, 2017 ONSC 1985 (CanLII) -

    Succeeded in obtaining temporary injunction prohibiting landlord from locking out tenant pending an appeal, even though the client’s application to permit him to renew his lease was dismissed. View decision here.
  • Halton Standard Condominium Corp No 627 v Grandview Living Inc, [2015] OJ No 7060 (QL) (Ont Sup Ct J) -

    Successfully represented a developer against a condominium board in a precedent-setting case
  • Voudouris v Appeal Tribunal of the Certified General Accountants' Assn of Ontario, 2014 ONSC 1865 (Ont Div Ct) -

    Successfully overturned a wrongful conviction of an accountant for professional misconduct. View decision here.
  • Mintz & Partners Limited v. Winter, 2013 ONSC 354 (CanLII) -

    Acted for prominent Canadian businessman in the enforcement of judgments. View decision here.
  • British Columbia (Securities Commission) v McLean, 2013 SCC 67 -

    Acted in an intervention on a securities law issue before the Supreme Court of Canada. View decision here.
  • General Electric Canada Real Estate Financing Holding Co v Liberty Assisted Living Inc., 2011 ONSC 6199 -

    Acted for lender in enforcing its security, appointing an investigative receiver and obtaining a non-dissipation order against the debtors
  • Nunavut (Department of Community & Government Services) v Northern Transportation Co, 2011 NUCJ 4, 2010 NUCJ 5 -

    Effectively represented the Government of Nunavut (GN) in a complex multi-million dollar products liability claim brought by the GN against the suppliers of defective gasoline that damaged over 2,000 snowmobiles owned by Inuit and other residents of Nunavut. View decision here.
  • Brisbin v Lunev, 2011 ONCA 15 -

    Acted for a prominent architectural firm in a contractional dispute that involved jurisdictional issues. View decision here.
  • Rannala v 1213321 Alberta Ltd, 2009 ONCA 659 -

    Acted for the plaintiff vendors in a dispute with the purchaser of the shares of a large kitchen cabinet manufacturer. View decisions here: 2009 ONCA 659, 2009 CanLII 2483.
  • West Hill Minor Hockey Assn v Scarborough Hockey Assn, [2009] OJ No 2171 (QL) (Ont Sup Ct J) -

    Acted for the Greater Toronto Hockey League, the world’s largest hockey league, in an internal governance dispute between the Scarborough Youth House League and West Hill Minor Hockey Association. View decision here.
  • Le Maitre Ltd v Segeren (2007), 33 BLR (4th) 224 (Ont Sup Ct J) -

    Successfully stopped a multi-million dollar transaction from proceeding at the behest of one shareholder who had not consulted or obtained approval for the deal from his client, resulting in a leading decision on the test for obtaining an injunction against a co-shareholder. View decision here.
  • Frayne v Holburn Business Systems Corp (2007), 156 ACWS (3d) 518 (Ont Sup Ct J) -

    Obtained a rare order for interim legal costs to be paid to his client by the other side before the case was to even be heard. View decision here.
  • Frontenac Ventures Corp. v Ardoch Algonquin First Nation, [2007] OJ No 3360 (QL) (Ont Sup Ct J) -

    Represented a First Nations band involving the blockade of uranium exploration on disputed aboriginal lands
  • Antonopoulos v Antonopoulos, [2006] OTC 105 (Ont Sup Ct J) -

    Successfully acted for husband in setting aside an order freezing the proceeds of sale of his interest in a business. View decision here.
 Recognition

Recognition

  • Recognized by Best Lawyers® in Canada 2026 in the area of Corporate and Commercial Litigation
  • Recognized by Best Lawyers® in Canada 2025 in the area of Corporate and Commercial Litigation
  • Voted by Lexology as the Legal Influencer in Canada in Q4 2018, Q1 2019, Q3 2019, Q4 2019, Q2 2020, Q1 2021, Q3 2021, Q2 2022, Q3 2023 and Q2 2025 for his contribution to the weekly blog, Blaneys Appeals. 
 Speaking

Speaking

 Publications

Publications

 In the Media

In the Media

 News

News

 Blogs

Blog Posts

 Memberships

Memberships

  • Law Society of Ontario
  • Ontario Bar Association (Past Chair, Civil Litigation Section Executive)
  • The Advocates’ Society
  • Toronto Lawyers Association
  • Hellenic Canadian Lawyers’ Association (Past President)
 Community

Community

  • Former Director, Hellenic Heritage Foundation, a charitable organization
  • Former Mentor, Ryerson University Law Practice Program, Law Society of Ontario Lawyer Licensing Program
  • Former Director, Pro Bono Community Legal Clinic, Hellenic Canadian Lawyers’ Association/Greek Community of Toronto/Pro Bono Law Ontario

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