From 1941 during World War II, Skouen was associated with the Norwegian Resistance Movement during the occupation of Norway by Nazi Germany.

After the liberation of Norway at the end of World War II, he returned to Dagbladet as a columnist, serving from 1946 to 1947.

During the war he published the children's play Barn av solen (1941) and Tre små enaktere (1943).

This was followed in the postwar years by his novels Fest i Port des Galets and Romanen Gategutter (1948).

He received international fame for his 1957 film Ni Liv, about Jan Baalsrud's survival following a failed a WWII commando raid in occupied Norway, which received an Academy Award nomination for Best Foreign Language Film.