Prime Minister of Australia prime minister, otherwise William McMahon63. Robert Menzies was the oldest person to ever be prime minister, leaving office at 71 years old. The longest-serving Prime Minister was Sir Robert Menzies, who served in office twice: from 26 April 1939 to 28 August 1941, and again from 19 December 1949 to 26 January 1966. In total Robert Menzies spent 18 years, 5 months and 12 days in office. He served under the United Australia Party and the Liberal Party respectively. The shortest-serving Prime Minister was Frank Forde, who was appointed to the position on 6 July 1945 after the death of
Prime Minister of Israel Basic Laws of Israel explicitly vest executive power in the government, of which the Prime Minister is the leader. The office of Prime Minister came into existence on 14 May 1948, the date of the Declaration of the Establishment of the State of Israel, when the provisional government was created. David Ben-Gurion, leader of Mapai and head of the Jewish Agency became Israel's first Prime Minister. The position became permanent on 8 March 1949, when the first government was formed. Ben-Gurion retained his role until late 1953, when he resigned in order to settle in the Kibbutz of Sde Boker.