Born in Glücksberg, Germany, he relocated to Norway where he made his stage debut at Nationaltheatret in 1918, and played for this theatre for many years.

Schwenzen was script writer and director for the 1922 film adaption of Knut Hamsun's Pan.

He chaired the Norwegian Actors' Equity Association during the occupation of Norway by Nazi Germany,[2] and was arrested and sent to Grini and Sachsenhausen concentration camps.

[3] After his release and the end of the war, he continued appearing on Norwegian stages and in films.

In 1948, Schwenzen played the role of the German general von Falkenhorst in the Operation Swallow: The Battle for Heavy Water.