The youngest prime minister upon their appointment by the Governor-General was Chris Watson, who was 37 years, and 18 days old when his term began on 27 April 1904.
How old was Chris Watson when he became Australian Prime Minister?
Prime Minister in 1904
He was aged only 37, and remains the youngest Prime Minister in Australia’s history.
What is the minimum age to be prime minister of Australia?
have reached the age of 18 years; be an Australian citizen; and. be an elector, or qualified to become an elector, who is entitled to vote in a House of Representatives election.