At the age of only 18, John Rumble was selected to represent Canada in equestrian at the 1952 Summer Olympics, but was dropped from the team after suffering an illness. Four years later he got a second chance and, at the 1956 Games, won a bronze medal alongside Jim Elder and Brian Herbinson in the three-day event. He was the strongest member of the team, accruing the fewest negative points and finishing 16th individually.
He was also an alternate on the 1960 Olympic delegation, but did not compete. He graduated from the University of Toronto with a bachelor’s of science degree and worked as a sales engineer before starting his own company selling mining vehicles in Western Canada. He has also been involved in the breeding and racing of horses; one of his animals, Foxwood High, helped Selena O’Hanlon win a silver medal in team eventing at the 2011 Pan American Games. In 2009 he was made an inaugural member of the Canadian Eventing Hall of Fame, alongside his bronze medal-winning team and their horses.