He was born in Skogn as a son of farmer Olaf Herman Sjaastad (1869–1944) and Marta Fostad (1870–1933). He enrolled as a student in 1922, and graduated with the cand.jur. degree in 1926. He opened an attorney's office in Namsos in 1927. From 1933 he was a barrister, with access to work with Supreme Court cases. He was a member of the executive committee of Namsosmunicipal council from 1927 to 1934, representing the Liberal Party, whose local party chapter he chaired from 1927 to 1931.[1]
In 1935 he opened a lawyer's office in Oslo.[1] During World War II he was a member of the Norwegian resistance movement. He was arrested in December 1940 for "spying", and was imprisoned until May 1941 at Møllergata 19. In February 1944 he was arrested for the second time, this time for being involved in an illegal newspaper. He was imprisoned at Møllergata 19 again, before being transferred to Grini concentration camp, where he sat from May 1944 to the war's end on 8 May 1945.[2]
^Giertsen, Børre R., ed. (1946). Norsk fangeleksikon. Grinifangene (in Norwegian). Oslo: Cappelen. p. 14. {{cite encyclopedia}}: Missing or empty |title= (help)