 After schooling in Bergen, Mohr went to a trading institute in Lausanne for two years followed by commercial training in Bremen and London for four years.In 1877, he entered the family firm "Aug. C. Mohr & Søn" which had first been founded by his grand father, August Christian Mohr (1775–1845).After his father's death in 1880, he became the head of the company together with his uncle Anton P. Mohr.