During the 1920s Reidar Raaen was one of the best cyclists in Norway, winning multiple national titles. Raaen won his first title in 1922 with victory in the 100 km individual time trial, also receiving the King’s Cup for his performance. He repeated this feat again in 1923 and 1924, before winning his fourth national time trial title in 1927. He also won the 30 km individual time trial title in 1924. On the track Raaen had similar success, winning the 10,000 metres at the Norwegian Track Cycling Championships for three consecutive years from 1923 to 1925. He later competed in the individual road race at the 1928 Amsterdam Olympics but did not finish the course.