While a student at the University of Oxford and at St. Mary's Hospital Medical School, London, Bannister won British (1951, 1953–54) and Empire (1954) championships in the mile run and the European title (1954) in the 1,500-metre event. He broke the four-minute barrier with a time of 3 min 59.4 s in a dual meet at Oxford on May 6, 1954. Breaking the world record (4 min 1.3 s), held for nine years by Gunder Hägg (Hägg, Gunder) of Sweden, was almost incidental to his successful defiance of the “psychological” barrier, the general belief in the impossibility of running a mile in less than four minutes. Bannister is said to have achieved his speed through scientific training methods and thorough research into the mechanics of running. He recounted his experiences in the book The Four Minute Mile (1955).

Bannister graduated from St. Mary's in 1954, earned a medical degree from Oxford in 1963, and became a neurologist. He wrote papers on the physiology of exercise, heat illness, and neurological subjects, and from 1969 on he edited Brain's Clinical Neurology (retitled Brain and Bannister's Clinical Neurology, 7th ed., 1990). He was knighted in 1975.