Jahn is the Leader of the Norwegian National Ballet Youth Company.

Started dancing with Bolshoi Ballet Balletschool.

Finished his dance education in The Norwegian Opera balletschool.

Professional work:
1985-1986 and 1988-1989 Norwegian National Ballet
1986-1988 Washington Ballet
1989-2006 Dutch National Ballet (Principal dancer and ballet master)
2006-2013 Norwegian National Ballet (Ballet Master and Assistant Director).

2013-2016 Head of classical ballet line with Oslo National Academy of the Arts.

2016-present Norwegian National Ballet (Assistant Director and from 2022 also Leader of NNB youth company, NNB UNG).

Principal dancer:
Danced leading roles in the classical ballets like Swan Lake, Giselle, Sleeping Beauty, Nutcracker, Romeo and Juliet, Cinderella, La Sylphide, Midsummer­night Dream, La Bayadere and Onegin.
Danced many principal/soloist roles in classical and neoclassical repertory like Etudes, Scene de ballet, Le Sylphide, Volunatries and principal/soloist roles in ballets from choreographers like G. Balanchine, W. Forsyth, M. Graham, K. Pastor, D. Dawson, W. Eagling, F. Ashton, H. van Manen,R. van Dantzig and L. Massine.
He has been guesting with companies and Galas in Germany, England, Italy, France, U.S.A., Spain, Russia, Lithuania and Norway.
In 2006 he stopped dancing and started to work as ballet master with Dutch National Ballet and and staged ballets in Latvia, Scotland, Netherlands, and Switzerland for different choreographers.