[1][2] Bjørnstad made his debut in 1945 at the People's Theater in Sweden.
He also made an impression in Cora Sandel's Kjøp ikke Dondi (Don't Buy Dondi) and Kido Okamoto's Heikegani (The Heike Crabs).
[citation needed]} In 1946, Bjørnstad made his film debut in Englandsfarere.
Other films that he appeared in include Jentespranget, Trost i taklampa, Den siste Fleksnes, and Olsenbanden gir seg aldri.
Bjørnstad also had some television roles outside of his Television Theater productions, including in a few episodes of the comedy series Fleksnes Fataliteter as well as in the crime series Nini (2001)[3] and Blind gudinne (1997).