Otto Falkenberg grew up in Alversund and Bergen, where his father worked. As a young man Falkenberg worked as a seaman on a ship of the Cunard line travelling to New York. He later held commercial positions as a clerk for a trading house in Dunkerque in France and as an accountant at Schøyens Bilcentraler, a bus company in Oslo, where he also became a real estate agent. In 1947, Falkenberg was sentenced to three years hard labor, fines and the loss of his real estate license under the legal purge after the German occupation of Norway.