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
Director of Communications (Office of the Prime Minister) at 5:30am and describing his day until roughly 11:00pm. Since 2006 only half of the directors have lasted more than one year, with the average in the position being just 395 days, or roughly 13 months. The longest serving director is Sandra Buckler, with over two years in the position, who was forced to leave in order to undergo cancer treatment. The shortest duration was just 32 days with William Stairs, who left shortly after Prime Minister Stephen Harper was elected with a minority government. Director of Communications (Office of the Prime Minister) The Director of Communications in the Prime