John Mikaelsson did running, cross-country skiing and played both football and handball, before taking up race walking in 1934. His breakthrough year was 1937, when he won the British AAA 7 miles track walk title with a new world record of 50:19.2, and he repeated that victory in 1938. Concentrating on shorter distances and track walking, Mikaelsson set 14 world records at various distances between 1936 and 1946. His best years as an athlete unfortunately came during World War II. Mikaelsson won his first major international title in 1946, when he won the 10 km walk at the European Championships, followed by victories in the 10 km walk at the 1948 and 1952 Olympics. At the 1950 European Championships, Mikaelsson won bronze in the 10 km walk. He retired from sports after the 1952 Olympics and emigrated to the United States in 1965, settling in California where he acted as a race walking referee in local competitions.

Personal Best: 10kmW ? 42:52.4 (1945).