Andersen, who started for Kjelsås IL and Bækkelagets Sports Club , had his first international success at the Nordic Junior World Ski Championships in 1993 in Harrachov . There he won the silver medal in the 30 km freestyle and the gold medal with the relay. He was also fourth there over 10 km classic. In December 1994 he ran his first race in the Continental Cup in Ilomantsi and came in 26th place over 10 km classic. He made his debut in the cross-country skiing world cup in February 1995 in Oslo , which he finished classically in 57th place over 50 km. In March 1995 he won second place in the Continental Cup in Kuusamo over 15 km freestyle and in Piteå he won the classic Continental Cup over 10 km for the first time. In the 1995/96 season he got his first World Cup points in Falun with the 16th place over 10 km freestyle and won over 30 km freestyle at the Continental Cup in Ylivieska . In February 1996 he reached the sprint at the World Cup in Reit im Winkl , for which there were no World Cup points, with fifth place, his best individual result in the World Cup. The following month he triumphed at the World Cup in Oslo with the relay. At the beginning of the 1998/99 season he won his third Continental Cup victory in Lillehammer over 5 km freestyle. In February 2002 in Nové Město he achieved his second and last top ten placement in the individual World Cup with ninth place over 10 km freestyle. In the 2004/05 season he came in the Scandinavian Cup four times in the top ten. He won the 15 km freestyle in Veldre and finished third in the overall ranking of the Scandinavian Cup at the end of the season. He completed his 43rd and last World Cup individual race in March 2006 in Oslo, which he finished in 36th place over 50 km freestyle. At Norwegian championships he came second five times and third three times.
Norway
Piteå
Ylivieska