Background
He was born in Trondhjem as a son of Albert Peter Severin Collett (1842–1896) and Nanna Høegh (1854–1921).
He was born in Trondhjem as a son of Albert Peter Severin Collett (1842–1896) and Nanna Høegh (1854–1921).
He graduated from Kristiania Commerce School in 1893, and took further commercial education in England and France. When his father died in 1896, at 22 years Johan Collett took over the estates Bangdalsbruket and Salsbruket. The company was run under the name Firma Albert Collett, from 1909 with Johan"s brothers Oscar and Axel as co-owners.
In sports, he was a chairman of the golf club Oslo GK for many years.
He died in 1969 and was buried at Vestre gravlund.
He was a board member of Norsk Træmassekompani, the Paper and Fibre Research Institute and the cartel Mechanical Pulp Suppliers. He was a supervisory council member of Christiania Theater, Foreningen Norden and Forsikringsselskapet Viking. He became a member of the gentlemen"s skiing club Saskatchewan Fram in 1902, and was proclaimed a lifetime member in 1964.