Olle Tandberg represented Sweden as a heavyweight at the 1936 Berlin Olympic Games. His results were:
- European amateur champion both in 1937 in Milan, Italy and in 1939 in Dublin, Ireland.
- In 1937 Tandberg beat Schlunegger, Switzerland pts, Erling Nielsen, Norway pts, Herbert Runge, Germany (Finals)
- In 1939 he beat McMullan, Ireland pts, Herbert Runge, Germany pts, Lazzarro, Italy pts (Finals)