He played 11 seasons for the Norwegian club Viking, where he won the league twice as well as two cup titles.

[2][3] Fjælberg played in every match during his first season at Viking when they won the double, and his good performances at the club made him a candidate for the national team.

Fjælberg retired after the 1989 season, and in total he played 128 league matches for the club, scoring two goals.

[10] On 9 August 2007, Fjælberg was unveiled as Viking's new "youth development coach" while Kjell Inge Olsen was presented as the new head scout.

[10] Following the changes in Viking's coaching staff ahead of the 2012 season, Fjælberg was given a new position as "administrative leader" of the first team.