He was born in South Shields as a son of shipmaster and navy captain Carl Gustav Jacobsen (1878–1941) and Frida Mørch (1878–1968).
He returned to Norway, where he finished his secondary education in 1932 before studying law at the University of Oslo.
degree in 1937 and studied at the London School of Economics before being hired in the Norwegian Ministry of Foreign Affairs in 1938.
He served as an attaché at the Norwegian legation in Paris, and had to flee the country in June 1940.
He then joined Borten's Cabinet as a non-partisan member, and was a State Secretary in the Ministry of Foreign Affairs from 1965 to 1970.