He was born in Skjeberg as a son of Anton Fredrik Andersen Torp (1865–1907) and Anne Bolette Andreassen Gade (1867–1932). He had eight siblings, and lost his father at a young age. His father worked in Canada from 1903, and sailed home to collect his family to emigrate to Canada in 1907. However he died en route, near Liverpool. Torp attended primary school before joining the workforce at age 13. He eventually became an electrician, and already at the age of 14 he became deputy treasurer in his local trade union. He also joined the Norwegian Labour Party, and was elected to the national board in 1918, when an opposition of revolutionaries assumed power in the party. Torp chaired the party chapter in Sarpsborg from 1919 to 1921 and in Østfold county from 1921 to 1923. He was also a supervisory council member in the Norwegian Confederation of Trade Unions from 1920 to 1925, and board chairman of Østfold Arbeiderblad from 1921 to 1923. He was married to Kari Hansen (1893–1967) since April 1916. He was the father of Reidar Torp.