There have been at least three American cinema actors named "John Hart". This article concerns the one who is probably best-known for temporarily replacing Clayton Moore on the television series version of The Lone Ranger.
John Hart is most famous as a New Zealand rugby coach, firstly for Auckland and for the All Blacks. He began his first class coaching career for Auckland in 1982 and achieved rapid and unprecedented success with them. His coaching reign of that province continued until 1986, during which time his Auckland team won the National Provincial Championship (NPC) all but one of the years.