Three times Prime Minister, Alfred Deakin was a member of the House of Representatives from 1901 to 1913. He was PM for two brief terms (1903–04 and 1909–10), and for three years from 1905 to 1908.

Deakin was the only PM to reject both the title 'Right Honorable' and membership of the Privy Council and also refused honorary degrees from Oxford and Cambridge universities.

Deakin's archival records are concerned with a range of topics from the foundations of Australian defence policy to the transfer of the Northern Territory to the Commonwealth in 1911.

Prime Minister in 1904 for less than four months, Chris Watson made history as the first head of a Labor government of any nation in the world. He was also Australia's youngest PM, serving in parliament until 1910, and developing business and investment interests, with motoring and the development of roads a key interest from the 1920s.

A founder of the Australian Labor Party, Watson remained an influential figure until he was expelled for his support of conscription in 1917 by the solidarity rule which he established.

Watson designed the soldier settlement scheme in 1917, was a trustee of Sydney Cricket Ground, a founder and first chairman of Ampol in 1936 and a founder of the NRMA.

Andrew Fisher was Prime Minister three times (1908–09, 1910–13 and 1914–15). He also served as Treasurer during each of these terms. He migrated from Scotland to Queensland in his early 20s and was a founding member of the Queensland Labor Party.

During his second term as PM the parliament passed a total of 113 acts. During his government the Royal Australian Navy and the Commonwealth Bank (1912) were established, the Northern Territory was transferred to the Commonwealth, and construction of the transcontinental railway began.

Fisher's government named wattle as Australia's national flower and put the wattle on Australia's Coat of Arms.

Margaret Fisher led the Australian group in the British suffrage march in London in 1911.

Cook began his political life as a Labor parliamentarian in New South Wales before Federation. He joined the first federal parliament in 1901 as member of the Free Trade Party. In 1917 he was a key figure in the formation of the Nationalist Party led by Hughes. After leaving politics, Cook was Australia's High Commissioner in London.

Cook was one of the 'Australian Lincolns' — those PMs whose early poverty meant they had left school as boys to take jobs.

William Morris Hughes was Australia's seventh Prime Minister. Hughes was Australia's longest serving federal parliamentarian. He was a member of Australia's first parliament in 1901 and he served 51 continuous years until 1952. He was a founding member of three Australian political parties:

• the Labor Party (1916)
• the Nationalist Party (1929)
• the United Australia Party (1944)

Hughes was expelled from them all. He sat as a member of the Liberal Party from 1945 to 1952. He was the longest serving PM until 1956 when Robert menzies overtook his record.

In 1915 Hughes founded the Advisory Council for Science and Industry, later the CSIRO.

Stanley Melbourne Bruce was prime minister for six years (1923–29), and a member of the House of Representatives for 13 years (1918–29 and 1931–33). In 1929 he became the first prime minister to lose his seat as well as his office (the second being John Howard in 2007).

Bruce's chief contribution to Australia was as an international statesman. He was Australia's High Commissioner in London (1933–45). Bruce was also strongly involved in the League of Nations.