He was born in Furnes as a son of Bernt Frydenberg (1868–1925) and Benedicte Charlotte Christiansen (1872–1953).
He worked in the Ministry of Social Affairs from 1921 to 1947, except for 1925 to 1926 when he was a deputy judge in Hadeland and Land District Court, and from 1939 to 1940 when he was a deputy under-secretary of state in the Ministry of Provisioning and Reconstruction.
In the Ministry of Social Affairs he was a clerk from 1921, assistant secretary from 1936 and deputy under-secretary of state from 1940.
He was responsible for the proposition of deporting German-Norwegian war children to Australia.
While living in Vest-Agder, he chaired the Kristiansand branch of Foreningen Norden from 1951 to 1954.