Dr. Johnston is a professor emeritus of dentistry at the University of Michigan, and a professor emeritus of orthodontics at Saint Louis University. He graduated from the University of Michigan School of Dentistry and from Michigan’s Horace H. Rackham School of Graduate Studies in orthodontics). He studied anatomy at the Queen’s University of Belfast and received a PhD in anatomy from Case Western Reserve University. Before coming to the University of Michigan, Dr. Johnston chaired the orthodontic departments of both Case Western Reserve University and Saint Louis University. At the University of Michigan, he chaired the Department of Orthodontics and Pediatric Dentistry and was the Robert Browne Professor of Dentistry.