Nash was born in Kidderminster, England, and is the most recent New Zealand prime minister to be born outside the country. He arrived in New Zealand in 1909, soon joined the original Labour Party, and became a member of the party's executive in 1919. Nash was elected to Parliament in the Hutt by-election of 1929. He was from the moderate wing of the Labour Party. Appointed as Minister of Finance in 1935, Nash guided the First Labour Government's economic recovery programme during the Great Depression and then directed the government's wartime controls. He succeeded Peter Fraser as Leader of the Labour Party and Leader of Opposition in 1951.