He was born at Frednes in Porsgrunn as a son of ship-owner Jørgen Christian Knudsen (1843–1922) and Marie Henriette Resch (1846–1925).
He translated books from English and French, and published a lexicon for merchantry and shipping (a re-issue of a work by C. F. Berg) in 1909.
He was elected to the Parliament of Norway in 1924 from the Market towns of Telemark and Aust-Agder counties and took a seat in the Standing Committee on the Military.
[1] During the occupation of Norway by Nazi Germany, Knudsen became a collaborator, serving as acting County Governor of Telemark in 1940.
During the legal purge in Norway after World War II he was sentenced in October 1947 to seven years of forced labour, loss of civil rights and a monterary confiscation.