Professor Sossin holds doctorates in Law from Columbia University and in Political Science from the University of Toronto. Prior to joining U. of T. in 2002, he was a faculty member at Osgoode Hall Law School, York University and was an Associate-in-Law at Columbia Law School. He is also a former litigation lawyer with Borden & Elliot (now Borden Ladner Gervais) and a former law clerk to the Chief Justice of the Supreme Court of Canada.
Professor Sossin is the author of over 50 articles and books including Boundaries of Judicial Review: The Law of Justiciability in Canada (Toronto: Carswell, 1999), Public Law (Toronto: Carswell, 2002) (with Michael J. Bryant), Access to Care, Access to Justice: The Legal Debate on Private Health Insurance in Canada (Colleen Flood, Kent Roach & Lorne Sossin, eds.) (Toronto: University of Toronto Press, 2005); and Dilemmas of Solidarity: Rethinking Redistribution in the Canadian Federation (Sujit Choudhry, Jean-Francois Gaudreault-Desbien & Lorne Sossin eds.) (Toronto: University of Toronto Press, 2006).
Professor Sossin is a frequent advisor to government and has been commissioned to write papers for the Gomery Inquiry, the Ipperwash Inquiry, the Panel on the Role of Government and the Expert Commission on Pensions, in addition to the Inquiry into Pediatric Forensic Pathology headed by Justice Stephen Goudge. He is a part-time member of the Health Professions Appeal and Review Board, and serves on the Boards of the Law Foundation of Ontario, Pro Bono Law Ontario, and the Ontario Justice Education Network. In 2008, he was appointed Investigator for the City of Toronto.
Professor Sossin is the Director of the Faculty of Law's new Center for the Legal Profession.