Expertise
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Practice Areas:
- Bar Admissions:
- Education:
- University of Western Ontario (2017) JD (Distinction)
- York University (2014) MA
- University of Western Ontario (2013) BA (Honours)
Details
- Bio
- Cases
- Associations
- Blog Posts
- News & Media
- Publications & Presentations
- Recognition
Sean Lewis (he/him)
is an associate at Lenczner Slaght.
"Sean Lewis is an excellent advocate. His research, writing and presentation skills are exceptionally strong." — Chambers Canada
Sean’s practice encompasses a broad range of litigation areas, including corporate-commercial, employment, public law, and professional liability.
Sean acts for a wide range of clients, including individuals, corporations across several industries, and governments. He also regularly defends the interests of physicians involved in regulatory and medical negligence matters.
Sean has appeared before several levels of court in multiple provinces, including the Ontario Court of Appeal and the Supreme Court of Canada, as well as multiple administrative tribunals.
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The Estate of KJM v The Estate of Dr. Naom
Counsel to the successful defendant physicians after a three-week trial in a medical negligence action arising from a patient who died of an aortic dissection four years after the diagnosis of an aortic root dilatation.
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Loblaw Companies Limited et al v Royal & Sun Alliance Insurance Company of Canada et al
Counsel to the appellant, AIG Canada in a duty to defend and coverage matter related to opiate class proceedings. Decision brought important clarity to defence obligations for long-tail claims and on satisfaction of self-insured retentions.
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Counsel to a property development company in a dispute regarding the sale of a partnership interest.
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NORR Limited v Encon Group et al
Counsel to an architecture firm in a coverage dispute with its insurer regarding a large scale construction project.
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Cameron Stephens Mortgage Capital v 272 Ontario Inc
Counsel to Cameron Stephens Mortgage Capital Ltd. in a dispute regarding an alleged breach of a loan agreement.
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Counsel to a defendant developer in an alleged oppression matter.
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Counsel to the successful Defendant Physician in a trial for alleged negligence in respect of cancer treatments.
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Grand Land Investments Inc v Cameron Stephens Mortgage Capital Ltd
Counsel to Cameron Stephens Mortgage Capital Ltd. in an action concerning the alleged breach of a commitment letter.
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Counsel to a physician in rare medical malpractice case before the Supreme Court of Canada, which discussed interesting issues relating to the standard of care.
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Assurant Life of Canada ats GFD
Counsel to the successful Respondent corporation in a breach of contract dispute concerning an alleged amendment to a contract.
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Advocates' Society
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Canadian Bar Association
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Ontario Bar Association
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Loblaw Companies Limited et al v Royal & Sun Alliance Insurance Company of Canada et al
In Canada, numerous class proceedings have launched on behalf of governments and individuals against entities involved in the manufacture and distribution of opioids. These actions claim wrongful acts and damages that extend over 23 years, raising important legal questions for the insurers of these entities as to the extent of their obligation to defend the proceedings on behalf of their insureds.
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“Next Exit, Please”: Escaping a Contractual Buy/Sell Process
Shareholder agreements commonly contain buy/sell provisions establishing a process by which a shareholder can initiate a sale of their interest or can acquire the interest of another shareholder. The particulars of this process vary. Based on the parties’ bargain at the time the agreement is made, there are frequently unique and particular requirements to these provisions. The Ontario Superior Court of Justice emphasizes the importance of abiding by those requirements, as seen in a recent decision invalidating a purported closing of a share purchase transaction for the purchasers’ failure to comply with the specific process set out in the Shareholders’ Agreement. Justice Vella’s reasons in Leeder Automotive Inc v Warwick therefore offer an excellent reminder to shareholders that they disregard the requirements of a buy/sell provision at their peril.
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The Court of Appeal for Ontario has once again reaffirmed the deference afforded to first instance judges in cases of contractual interpretation that rely heavily on the factual matrix—even where the underlying facts and history are unique.
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The SCC Leave Project: Predictions for May 13, 2021
Here’s a look at the leave application decisions that the Supreme Court of Canada will be releasing on May 13, 2021.
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In its February 28, 2020 decision, Nevsun Resources Ltd v Araya, the Supreme Court of Canada allowed a claim by three Eritrean citizens against a British Columbia corporation operating in Eritrea to proceed. Canadian (and international) corporations with international operations in high risk jurisdictions should take note.
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Enforcing Arbitral Awards on the Commercial List
Lawrence E. Thacker and Sean Lewis co-authored the article Enforcing Arbitral Awards on the Commercial List, which was published on commerciallist.com.
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Lexpert’s Top 10 Business Decisions of 2023–2024
Lenczner Slaght was featured twice in Lexpert's Top 10 Business Decisions of 2023-24 for its involvement in Loblaw Companies Limited v Royal & Sun Alliance Insurance Company of Canada and Yatar v TD Insurance Meloche Monnex.
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Lenczner Slaght Litigators Recognized as the Best Lawyers in Canada
In the 2025 edition of Best Lawyers in Canada, Lenczner Slaght is proud to receive 168 total rankings, with 45 of our expert litigators recognized for their expertise across 25 practice areas.
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Still much to be determined on insurance coverage after cyberattacks
Sean Lewis is quoted in the Law times article "Still much to be determined on insurance coverage after cyberattacks" on August 12, 2019. This article discusses case law related to cybersecurity insurance coverage.
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Lenczner Slaght Welcomes Five New Associates
Canada’s leading litigation firm continues to add to its collective experience and knowledge with the addition of five talented associates.
Lenczner Slaght is delighted to welcome Derek Knoke, Graham Henry, Jonathan D. Langley, Sean Lewis, and Zachary Rosen to the firm as our new associates.
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Lenczner Slaght Advocacy Competition in Legal Ethics and Professionalism 2025
Risa Kirshblum, Sean Lewis, Andrew Locatelli, Nicole Naglie, Joudy Sarraj, and Kyle Magee participated as judges at Western Law’s Annual Advocacy Competition in Legal Ethics and Professionalism.
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2024 Snapshot: Through the Lens of Lenczner Slaght
Lenczner Slaght launches our 2024 Snapshot, which highlights the most significant developments, decisions, and trends in litigation from the past year across 20 areas of expertise. Reflect on 2024 and look ahead to 2025 through the lens of our expert litigators.
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Lenczner Slaght Advocacy Competition in Legal Ethics and Professionalism 2024
We were proud to continue our sponsorship of Western Law’s Annual Advocacy Competition in Legal Ethics and Professionalism. Madison Robins, Sean Lewis, Bonnie Greenaway, Sahar Talebi, and Kyle Magee participated as judges.
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Be Careful What You Wish For (or, Be Careful What Contest Winner You Give Shares To)
Sean Lewis authored the blog Be Careful What You Wish For (or, Be Careful What Contest Winner You Give Shares To), which was published on commerciallist.com.
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2023 Snapshot: Through the Lens of Lenczner Slaght
Lenczner Slaght launches our 2023 Snapshot, a look at the most significant developments, decisions, business takeaways, and trends in litigation from the last year, across 15 practice areas. Revisit 2023 and look ahead to 2024 through the lens of our expert litigators.
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From Gold Mining in the Nevada Desert to Seeking Declaratory Relief on the Commercial List
Lawrence E. Thacker and Sean Lewis co-authored the blog From Gold Mining in the Nevada Desert to Seeking Declaratory Relief on the Commercial List, which was published on commerciallist.com.
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Lenczner Slaght Advocacy Competition in Legal Ethics and Professionalism 2023
We were proud to continue our sponsorship of Western Law’s Annual Legal Ethics and Professionalism Moot! Matthew B. Lerner, Sean Lewis, Sean Blakeley, Jim Lepore, and Allison Jandura participated as judges.
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The Walker Health Law Moot 2021
Sean Lewis, Vinayak Mishra, and Adam H. Kanji served as judges at the 2021 Walker Health Law Moot.
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Best Lawyers in Canada (2025)
Ones to Watch – Corporate & Commercial Litigation