William Morris "Billy" Hughes (25 September 1862 – 28 October 1952), Australian politician, was the seventh Prime Minister of Australia, from 1915 to 1923.
Over the course of his 51-year federal parliamentary career (and an additional seven years prior to that in a colonial parliament), Hughes changed parties five times: from Labor (1901–16) to National Labor (1916–17) to Nationalist (1917–30) to Australian (1930–31) to United Australia (1931–44) to Liberal (1944–52). He was expelled from three parties, and represented four different electorates in two states.
Originally Prime Minister as leader of the Labor Party, his support of conscription led him, along with 24 other pro-conscription members, to form National Labor. National Labor merged with the Commonwealth Liberal Party to form the Nationalist Party. His prime ministership came to an end when the Nationalist party was forced to form a coalition with the Country Party, who refused to serve under Hughes. He was the longest serving prime minister up to that point, and the fifth longest serving over all. He would later lead the United Australia Party to the 1943 election, though Arthur Fadden served as Coalition leader.
He died in 1952 at age 90, while still serving in Parliament. He is the longest-serving member of the Australian Parliament, and one of the most colourful and controversial figures in Australian political history.