Gjerstad played in the trio Detail together with the British drummerJohn Stevens, in the period 1981–1994, and they released fourteen albums. Other members of the band were the pianistEivin One Pedersen (1981–82) and the mega bassist's Johnny Dyani (1981–1986) or Kent Carter (1987–1994).
In 1985, he initiated "Circulasione Totale Orchestra", a band with varying lineups, where young musicians, mostly from Stavanger, could get a chance. To the Moldejazz 1989 he composed the commissioned work Dancemble which was performed by a 13-man version of the band. The band was active until 1995 and produced three recordings. In 1998, the band reemerged and released the album Borealis.
He also collaborated with numerous musicians in various small groups, which has resulted in several albums, tours and festival recordings in Norway, United States and Europe. The most long-lasting partnership in recent years is the current issue of Gjerstad Trio where he plays with drummer Paal Nilssen-Love and bassist Øyvind Storesund. They debuted at Nattjazz in Bergen 1999 and have released five albums.
Honors
1996: Jazz Musician of the Year by "Foreningen norske jazzmusikere"
