married Eliza Maud Barrett at Trinity Church, Perth. They had two sons and two daughters together. His great-granddaughter Jane Prentice was elected to federal parliament in 2010. Political career In 1893, Pearce helped found the Progressive Political League, a precursor to the Western Australian branch of the ALP. He was elected to the Subiaco Municipal Council in 1898. Self-educated in politics and economics, in 1901 he was elected to the first Commonwealth Parliament as a Senator for Western Australia. He narrowly missed out on being a member of the first Labor Party Cabinet when Chris Watson became Prime Minister in 1904. Pearce was Chairman of Committees in the Senate from 1907 to 1908. In 1908, Pearce was elected to cabinet by the ALP caucus as a member of the first Fisher Ministry. He had long shown an interest in defence matters in the Senate and was chosen by Prime Minister Andrew Fisher to become Minister for Defence. He believed it was his duty as minister to accept "any reasonable expenditure on armament, ammunition, and accoutrements" recommended by his advisers and to resolve disagreements between sections of the military. During his first term as minister, Pearce ordered three River-class torpedo-boat destroyers for the what would become the Royal Australian Navy. Pearce regained the defence portfolio in the second Fisher Ministry (1910–1913). During his second term as minister, he was responsible for the Naval Defence Act 1910, which created the Australian Commonwealth Naval Board and the Royal Australian Naval College. He attended the 1911 Imperial Conference in London where the relationship between the Royal Navy and Royal Australian Navy was determined. He oversaw the implementation of the Universal Service Scheme of compulsory military training scheme, and in 1912 approved the creation of the Central Flying School at Point Cook, Victoria, which became the "birthplace of Australian military aviation". World War I In 1914, Australia entered World War I. Upon Billy Hughes' ascension as Prime Minister, Pearce was named Deputy Leader of the party. Pearce served as acting prime minister from January to August 1916, while Hughes was in England and France. He was the first senator to hold the position, and the only senator to do so until Bill Spooner in 1962. Outside of the defence portfolio, Pearce oversaw the creation of Advisory Council of Science and Industry, the predecessor of the CSIRO, which Hughes had approved before his departure. In March