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
Office of the Prime Minister (Canada) Progressive Conservative (Tory) Prime Minister Brian Mulroney similarly had a powerful and active PMO, preferring advice he received from his staff than that which came from civil servants (whom he considered to be Liberal-leaning), or from those in the fractious Tory party. After Jean Chrétien was appointed as prime minister, the PMO continued to be the central organ of the government. Chrétien greatly depended upon the PMO, especially his chief of staff, Jean Pelletier, who ran the office from 1993 to 2001, Percy Downe, who served as his director of appointments from 1998 to 2001 and chief of staff from