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
Bob Hawke deregulated the financial sector, introduced the Family Assistance Scheme, announced "Advance Australia Fair" as the official national anthem, initiated superannuation pension schemes for all workers and oversaw passage of the Australia Act that removed all remaining jurisdiction by the United Kingdom from Australia. Hawke was replaced by his deputy Paul Keating at the end of 1991. Hawke remains Labor's longest-serving Prime Minister, Australia's third-longest-serving Prime Minister, and at the age of , Hawke is the oldest living former Australian Prime Minister. Hawke is the only Australian Prime Minister to be born in South Australia, and the only one raised and