 Andersen participated in Athletics at the 1900 Summer Olympics in Paris and competed in two field events, and won the bronze medal in the pole vault, he jumped 3.20 metres and finished behind two Americans Irving Baxter and Meredith Colket, earlier in the day he had competed in the high jump and jumped 1.70 metres to finish tied for fourth place just 0.5 metres behind another bronze medal.At the 1906 Intercalated Games in Athens, he was a member of the Norwegian gymnastics team, which consisted of 20 gymnasts, and went on to win the gold medal in the team, Swedish system event ahead of Denmark, he also competed in the individual all round five events competition and finished in 23rd position.Andersen also competed at the 1908 Summer Olympics in London, again he was part of the Norwegian gymnastics team that participated in the All round team event, and this time they finished in second place behind the Swedish team.