Dr. Bethune was born in Gravenhurst, Ontario, Canada. He moved to Montreal after graduating from the medical school of University of Toronto. He was associated with McGill University and taught thoracic surgery. Bethune was an early proponent of universal health care.
As a doctor in Montréal, Bethune frequently sought out the poor and gave them free medical care. As a thoracic surgeon, he travelled to Spain (1936-1937) and China (1938-1939) to perform battlefield surgical operations on war casualties.
During the Spain Civil War (1936-1937), the need to provide blood transfusions in a battlefield context led Dr. Bethune to develop the first mobile medical unit for transporting blood. This mobile medical unit was used as the model for the later development of Mobile Army Surgical Hospital (MASH) units.
Bethune died on November 12, 1939, of blood poisoning from a cut he received while performing surgery, while with the Communist Party of China's Eighth Route Army in
the midst of the second Sino-Japanese War.