As both a professor at Arizona State University College of Law and a Circuit Judge of the United States Court of Appeals for the Ninth Circuit, Canby has become known as an authority on American Indian law. He has authored law review articles, a major textbook, and the West Nutshell Series primer on the subject. While still a professor at ASU, Canby successfully argued the case of "Bates v. State Bar of Arizona", in which the Supreme Court held that the First Amendment allows lawyers to advertise in a manner that is not misleading to members of the general public.