Justice Lorne Sossin was appointed to the Ontario Superior Court of Justice in December, 2018. Prior to his appointment, Justice Sossin served as Professor and Dean of Osgoode Hall Law School, at York University (2010-2018). Previously, Justice Sossin was a Professor with the Faculty of Law at the University of Toronto (2002-2010). He is a former Associate Dean of the University of Toronto (2004-2007) and served as the inaugural Director of the U. of T. Centre for the Legal Profession (2008-2010). His teaching and research interests spanned administrative and constitutional law, civil litigation, legal ethics and the judicial process.

Justice Sossin was a law clerk to former Chief Justice Antonio Lamer of the Supreme Court of Canada, a former Associate in Law at Columbia Law School and a former litigation lawyer with the firm of Borden & Elliot (now Borden Ladner Gervais). He holds doctorates from the University of Toronto in Political Science and from Columbia University in Law.

Justice Sossin has published numerous books, journal articles, reviews and essays, including Administrative Law in Practice: Principles and Advocacy (Toronto: Emond Montgomery, 2018) (with Emily Lawrence); Middle Income Access to Justice (Toronto: University of Toronto Press, 2012) (co-edited with Tony Duggan and Michael Trebilcock); and Boundaries of Judicial Review: The Law of Justiciability in Canada 2nd ed. (Toronto: Carswell, 2012).