In October 1877 he married Emilie Josefine Sundbye. The couple had seven daughters and four sons.[2]
Career
An instrument maker by profession,[3] Gjøsteen became involved in the growing worker's movement in Norway. He became a member of Kristiania Arbeidersamfund in 1871, and as political parties were established in the 1880s, Gjøsteen joined the radical wing of the Liberal Party. From 1888 to 1891 he chaired De forenede norske arbeidersamfund.[1]
In the field of education, Gjøsteen served as a member of the school board in Kristiania from 1896 to 1923, chairing it from 1914 to 1919. He worked to build the public primary school into a basis for further education, and to strengthen the secondary education. He strongly supported the idea of the comprehensive school, to the point of being called "the father of the comprehensive school in Norway".[1][3]