Before joining Torys, John worked as a constitutional lawyer with the Ontario government and senior policy adviser with the Ontario Cabinet Office. He also spent two years teaching international trade law, international commercial arbitration and international human rights law at Otago University in New Zealand. Further, he served as a clerk to Mr. Justice Cory of the Supreme Court of Canada and the judges of the Ontario Court of Appeal.

John teaches International Commercial and Investor-State Arbitration and Public International Law at the University of Toronto Faculty of Law as an Adjunct Professor and teaches advocacy with the Foundation for International Arbitration advocacy in Geneva.

He is the co-author of the forthcoming Canadian Encyclopedia Digest’s International Law Title as well as three other books: Creditors' Remedies in Ontario; Interlocutory Proceedings: Strategy and Practice; and The Emotional Consequences of Personal Injury: A Handbook for Psychiatrists and Lawyers. He has also written numerous other articles and delivered speeches, primarily on international law and constitutional issues.