John Coleman Nunemaker was born October 5, 1910 in his grandfather's house in La Junta, Colorado. While still an infant, his parents moved to Twin Falls, Idaho. His mom was a substitute teacher and his father ran a gas station. Nunemaker completed his pre-med degree at the University of Idaho from 1928 to 1932. After his masters was finished, he went to Harvard Medical School, graduating with an M.D. in Internal Medicine in 1937. He had internships at Peter Brent Brigham and Johns Hopkins before going to the University of Michigan in Ann Arbor for his residency.

When World War Two was in full swing, Nunemaker joined the United States Army. He was sent to Fort Carson, Colorado to treat Italian prisoners of war (POWs). After Victory in Europe (V.E.) Day, he was then sent to Cairo, Egypt to treat men from the Battle of the Bulge who had developed trench foot. It was here that he met his future wife, who at that time was working for the Red Cross. After the war, they married in 1946 and moved to Salt Lake City, Utah. Here Nunemaker worked for a former professor in research.

Later in his life Nunemaker worked in Washington, D.C. for the Veteran Affairs office during the Eisenhower administration. In 1958, he and his family moved to Evanston, Illinois where he worked for the American Medical Association (A.M.A.) on their council on medical education. In 1970, Nunemaker became the first director of the American Board of Medical Specialties until he retired in 1976. He and his mother moved to Las Cruces, New Mexico where he eventually bought a seven acre pecan farm. John Coleman Nunemaker died from congestive heart failure on August 13th, 2000, just before turning 90 years old.