Sean Matheson Grassie

Sean maintains a broad litigation practice, with a focus on commercial and estates litigation, media and public law, and appellate advocacy. Sean’s clients value his measured and strategic approach to litigation, strong courtroom advocacy skills, and his ability to find practical solutions to complex problems.

Sean has appeared as counsel at all levels of court in Ontario, the Federal Court, the Federal Court of Appeal, and in commercial arbitration proceedings.

In his commercial law practice, Sean represents clients litigating contract and shareholder disputes, oppression remedy cases, and employment law matters. In 2024, Sean was lead counsel to a volunteer who successfully obtained relief from the Ontario Superior Court for his wrongful termination by a large national non-profit organization ( Hannan v. Scouts Canada , 2024 ONSC 5361 ). The Court’s decision has been described as a “landmark” in employment law that will have a “significant impact on the way in which not-for-profit and charitable organizations manage volunteers”. The case received widespread media coverage, including by the CBC , the National Post and the Ottawa Citizen .

In his administrative and public law practice, Sean represents clients in judicial reviews in the Divisional Court and Federal Court. In 2024, Sean successfully defended a public school board from a challenge to its disciplinary process.

Sean is a proud member of the Canadian Media Lawyers Association. He acts for national media outlets in cases involving court openness, freedom of expression, and other fundamental principles of Canadian democracy.

Prior to joining Conway, Sean completed two clerkships: in 2021-22 for the Honourable Justice Suzanne Côté at the Supreme Court of Canada, and in 2020-21 for the Honourable Justices David M. Brown, David M. Paciocco, and Lorne Sossin at the Court of Appeal for Ontario. Before clerking, Sean articled in the litigation department at a leading national firm in Toronto.