During World War II he participated in resistance work in Norway, until he fled to Sweden and Great Britain in 1944.

He joined as ground crew at the Norwegian Spitfire Wing, and participated at the war front in Belgium, Holland and Germany.

[1] Sverdrup made his literary debut in 1948 with the poetry collection Drøm og drift.

[3] His literary breakthrough came with the collection Sankt Elms ild from 1958, which earned him the Norwegian Critics Prize for Literature.

[4] During the 1960s he issued the poetry collections Isbjørnfantasi (1961), Sang til solen (1964) and Farlig vind (1969), and the prose books Negeren og solsikken (1965) and Paradisets barn (1968).