He is best known for his "Elling" tetralogy: Utsikt til paradiset (1993), Fugledansen (1995), Brødre i blodet (1996), and Elsk meg i morgen (1999).

[1] Brødre i blodet ("Blood brothers") was turned into a successful movie, entitled Elling, which received an Oscar nomination in the Best Foreign Film category in 2001.

Born in Tønsberg and raised in Larvik, his semi-autobiographical debut novel 23-salen ("The 23rd Row"), criticized mental health care in Norway.

The books Døden på Oslo S, Giftige Løgner, and De Blå Ulvene of this series were also turned into successful movies.

[2][4] His three Samson and Roberto books have become particularly popular in Russia, in part due to the illustrations by Nikolay Vorontsov, which also contribute carefully orchestrated local Russian-related colloquialisms to the stories.