He was born in Furnes as a son of Bernt Frydenberg (1868–1925) and Benedicte Charlotte Christiansen (1872–1953). In 1931 he married Major's daughter Marie Catharina Knap. He studied from 1917 and graduated from the Royal Frederick University with the cand.jur. degree in 1921. 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. As deputy under-secretary of state in the Ministry of Social Affairs. He was responsible for the proposition of deporting German-Norwegian war children to Australia. He was then the County Governor of Vest-Agder from 1948 to 1954 and the County Governor of Hedmark from 1954 to 1966.
He was active in the organizations Østlandsk reising and Østlandsk ungdomsfylking (chair from 1926 to 1927). From 1923 to 1926 he edited their magazine Østaglett. Their goal was to incorporate Eastern Norwegian spoken language into the country's official written language. While living in Vest-Agder, he chaired the Kristiansand branch of Foreningen Norden from 1951 to 1954. While living in Hedmark, he chaired Hedmark Museum and Domkirkeodden from 1955, and Hamar/Elverum Hospital from 1964 to 1968. He was a board member of Opplandskraft from 1954 to 1966. He was a member of several other councils during his career, and was involved in arbitration.
- Steenstrup, Bjørn, ed. (1973). "Frydenberg, Alf Birger". Hvem er hvem? (in Norwegian). Oslo: Aschehoug. p. 165. Retrieved 30 March 2011.
- Aarnes, Helle (19 March 2008). "Ville sende tyskerbarna til Australia". Bergens Tidende (in Norwegian). Retrieved 2008-09-08.
- Norwegian Counties — World Statesmen.org
- "Cemeteries in Norway" (in Norwegian). DIS-Norge. Retrieved 30 March 2011.
|County Governor of Vest-Agder
Knut Monsen Nordanger
|County Governor of Hedmark