Butler became the parliamentary leader of an informal group of country members supported by the Farmers and Producers Political Union in 1904. Butler was Treasurer of South Australia in the Jenkins ministry from 15 May 1901 to 1 March 1905, and was also Commissioner of Crown Lands and Immigration from 1 April 1902 to 1 March 1905. Jenkins then went to London as Agent-General. Butler succeeded him as Premier, still keeping his previous portfolios. His ministry was defeated soon after the 1905 election where Labor formed government under Thomas Price and retained government at the 1906 election, relegating Butler to opposition until a year before the 1910 election, when Labor lost government resulting from Price's death. The Liberal and Democratic Union (LDU) insisted on taking the premiership. On 22 December 1909 Butler joined the first Peake LDU ministry as Treasurer and Minister for the Northern Territory, but the ministry was defeated following the 1910 election. Following the 1912 election, Butler was Commissioner of Public Works in the second Peake ministry from 17 February 1912 to 10 November 1914 and Minister of Mines and of Marine from 17 February 1912 to 3 April 1915. The Peake government was defeated at the 1915 election, however Labor split over conscription in 1917 which brought down the government. Butler was Treasurer once again and Minister of Railways in Peake's third ministry from 14 July 1917 to 7 May 1919, and Minister of Agriculture 19 December 1918 to 7 May 1919.