Andersen was born in Kristiansund and played for Clausenengen before he joined Molde ahead of the 1995 season. He played for the Tippeligaen side until the summer of 1999, when he was sold to Wimbledon, right before Molde's Champions League matches against Mallorca. Molde's head coach Erik Brakstad stated in 2011 that if the club had not sold their best player (Andersen), Molde could had advanced from the group stage of 1999-2000 UEFA Champions League.

After playing for Wimbledon for four seasons, Andersen moved to Denmark to play for Aalborg in the Danish Superliga in 2003, before being bought by rivals Brøndby in September 2005. In April 2006, he suffered a knee injury. As he had not recovered by March 2007, Andersen considered retiring from the game.

Andersen played 38 matches for the Norway national football team. He was in roster for Euro 2000. His last international match was an April 2005 friendly match against Estonia.

Honours: Verdens Gang Norwegian Premier League Player of the Year 1999