William Charles Mercer

William Mercer is a fluently bilingual associate specializing in insurance defense and commercial litigation with a strong foundation in pro bono advocacy and community leadership.

William Mercer is a fluently bilingual associate lawyer at Summit Law LLP where he practices insurance defence with experience in tort liability, accident benefits, coverage disputes, and jurisdictional matters. He has appeared before the Superior Court of Justice, Small Claims Court, and several tribunals, and frequently represents clients at mediations and arbitrations. William holds both a Juris Doctor (Common Law) and a Bachelor of Laws (Civil Law) from the Université de Montréal, as well as a Certificate in Corporate Social Responsibility and Mediation from Université Aix-Marseille. Called to the Ontario bar in 2023, he is an active member of Canadian Defence Lawyers, where he contributes to the Accident Benefits Sub-Committee and Young Lawyers’ Committee, and Eagle International Associates’ Diversity and Inclusion Committee. In 2026, William is slated to begin his LL.M. in International Business Law at Osgoode Hall Law School, which he will pursue while maintaining a full-time practice at Summit Law LLP. Outside his legal practice, William is Co-Chair of the Young Philanthropists of the Montreal Museum of Fine Arts, a Board Member of the artist residency Adélard in the Eastern Townships of Québec, and a volunteer speaker with GRIS Montréal, advancing 2SLGBTQAI+ awareness in schools. When not at his desk, you can find him running anywhere there’s a flat trail and a good city view.