Willoch was born on 3 October 1928, in Oslo, to Haakon Isaachsen Willoch (1896–1955) and his wife Agnes Christine Saure (1895–1994). He grew up in the West End of Oslo, and took examen artium in 1947. After that, he studied economics at the University of Oslo, where he was taught by the Nobel Prize winners Trygve Haavelmo and Ragnar Frisch. He graduated with the cand.oecon. degree in 1953. Since 1951, Willoch was a member of the Oslo city council, and in 1954 he became a deputy in the Parliament of Norway. He became a member of parliament after the 1957 parliamentary election, and was with 29 years the then youngest MP.