[1] As a Germanophile, his thinking clashed with the Norwegian cultural nationalism of Nasjonal Samling chairman Vidkun Quisling.
During the German occupation of Norway, from 1940 to 1945, he worked as a defender for members of the Norwegian resistance who were tried in Nazi-controlled courts.
[5] Nonetheless, as a part of the legal purge in Norway after World War II, Wiesener received a small sentence for a piece he wrote in 1940.
[1] He was active in the Nazi movement in the spring and summer of 1940, when Quisling's first period as a national leader was over, and the German occupants tried to find Germanophile collaborators in the Norwegian society.
Wiesener held lectures in the German-controlled Norwegian Broadcasting Corporation, as did people like Jonas Lie, Johan Bernhard Hjort, and Ranik Halle.