He was born in Kristiania as a son of Ole Wettre (1830–1898) and Christine Elisabet Johannesen (1833–1920).
[2] After finishing Kristiania Commerce School in 1890, Wettre worked office jobs in Norway until 1907, except for the period 1893 to 1899 when he stayed abroad.
[4] In 1916 he entered the first board of the Scandinavian American Assurance Corporation, together with L. S. Karlsen, Harald Hougen and B.
[1] During prohibition in Norway (which was discontinued followed a 1926 referendum), Wettre was dispatched to conduct various negotiations with wine exporting countries: in Paris in 1923, Madrid in 1924 and Rome 1925.
He was also decorated as a Chevalier of the Legion of Honour and Commander of the Order of the Crown of Italy.