How long was Gustav Heinemann officially the President of the Federal Republic of Germany?
Gustav Heinemann:  He was Mayor of the city of Essen from 1946 to 1949, West German Minister of the Interior from 1949 to 1950, Minister of Justice from 1966 to 1969 and President of the Federal Republic of Germany (West Germany) from 1969 to 1974. President of Germany: The President of Germany, officially the President of the Federal Republic of Germany (German: "Bundespräsident der Bundesrepublik Deutschland" ), is the head of state of Germany.
from 1969 to 1974.