Before teaching law at Cornell University, Gray Thoron engaged in private law practice and was Assistant to the Solicitor General of the United States Department of Justice. He later joined the Cornell faculty, and from 1956 to 1963 was Dean of the Law School. His field of teaching and research includes criminal law, procedure (criminal and civil), professional ethics, and practice. He has participated in many national programs, in the activities of Bar Associations; in educational programs at Universities, including Texas, Michigan, and the Salzburg Seminar in American Studies. He served on the Overseers Committee to the Harvard Law School from 1960-1966. He is a Fellow of the American Bar Foundation and a member of the New York State Bar Association's Committee on State Constitutional Revision and the Association of American Law Schools' Committee on Academic Freedom and Tenure.