The German occupation ended on 8 May 1945, and the exiled politicians returned home. Torp chaired the Government Delegation from London to Oslo on 14 May 1945, and until 31 May 1945 he was thus the acting Prime Minister and acting Minister of Foreign Affairs in Oslo.

Much because of his exile, Torp was no longer found fit to be party chairman, and was replaced, against the party by-laws. He was also demoted to Minister of Provisioning and Reconstruction in Gerhardsen's Second Cabinet. He was pressured to leave this office as well, and left on 10 January 1948. He sat through his parliamentary term to which he had been elected in 1945; until 1948 the deputy Eugen Amandus Pettersen had taken his seat. He was also the Labour Party parliamentary leader. He moved to Vestfold in 1948 as he was appointed County Governor there. After a short time, he decided to stand for election again, and in 1949 he was elected for the Market towns of Vestfold county. In the same year he was one of the architects behind the Norwegian NATO membership.