Bergendahl is best known as the producer behind the films based on novels by Astrid Lindgren.
[3] In 1957 Bergendahl lived along with the production manager of Europafilm in an apartment in Stockholm.
The production manager told Bergendahl to apply for a job at the film company.
In 1984 he started working with Astrid Lindgren and produced Ronia, the Robber's Daughter.
He worked along with Astrid Lindgren, Tage Danielsson, Bo Widerberg, Lasse Hallström, Helena Bergström and many others.