A member of the Social Democratic Party, he was elected to the Bundestag (Parliament of the Federal Republic of Germany) in 1953. He was Minister of Defence (1969–72) and of Finance (1972–74). Elected federal Chancellor in 1974, following the resignation of Willy Brandt, he served for a second period (1978–82), during which he increasingly lost the support of the left wing of his party and of the Green Party.