Andreasson, who started for the IFK Mora SK and the Laisvalls SK, made his debut in Falun in February 2000 in the cross-country skiing world cup , which he finished in 11th place with the relay. He ran his first race in the Continental Cup in Orsa in December 2000 and finished 62nd in the sprint. In March 2001 he completed his first of a total of 19 individual World Cup races in Borlänge . He achieved 76th place over 10 km freestyle. In the 2005/06 season he came in the Scandinavian Cup four times under the top ten and thus achieved seventh place in the overall standings. In January 2006 he finished second at the Marcialonga . At the Wasalauf in March 2006, which was also classified as a World Cup race, he took sixth place, his first and only World Cup points. In November 2008 he achieved his first and only podium finish in the World Cup with second place in the relay in Gällivare . His only podium finishes in the Scandinavian Cup he achieved in February 2008 in Sundsvall with third place in the 30 km freestyle and in February 2010 at Spåtind with second place in the 15 km handicap race. In 2009 he won the Swedish championships with the relay of IFK Mora SK. In the 2010/11 season he reached ninth place in the cross-country skiing marathon cup with four top ten placements. Andreasson also took part in FIS races from 2000 to 2011 . He got six wins.