Martin was born August 23, 1876, in Norwich, Ontario, and died June 22, 1970, in Regina. He was a member of Parliament from 1908 until 1916 and served as Premier of Saskatchewan from 1916 until 1922, when he was appointed to the Saskatchewan Court of Appeal, serving from 1922 until 1961. He married Violette Florence Thompson of Mitchell, Ontario, in 1905. They had three sons.
Martin received his education in the Exeter public school and Clinton Collegiate in Huron County. In 1894 he entered the University of Toronto where he distinguished himself, both as a scholar and as an athlete. He graduated in 1898 with an honours degree in classics, and then attended the Ontario School of Pedagogy in Hamilton where he obtained a teacher's certificate. He taught for two years in Wellington County before returning to study law at Osgoode Hall. In 1903 he joined the law firm of his cousin, James Balfour, in Regina. Both the Martin and Balfour families had been active in Reform/Liberal politics in Ontario, and the Balfour law firm was also active in Liberal politics. In 1905 Walter Scott, the federal member of Parliament for Assiniboia West, resigned his seat to become the first Premier of Saskatchewan. In the 1908 federal election William Martin won the newly created Regina constituency.
Martin became an effective spokesman for western interests, including the need for more railways, reduced freight rates, the incorporation of grain growers' organizations, and other economic, legal and farm related issues. He also addressed law reforms and the North-West Mounted Police, which had its western headquarters in Regina. He won re-election in 1911, strongly supporting the Liberal Unrestricted Reciprocity policy. He also advocated federal assistance for the construction of a proposed railway to Hudson Bay.
In 1916 the Saskatchewan provincial government became embroiled in charges of patronage, political corruption, and a bitter school policy dispute with some Protestant church leaders. Premier Scott suffered ill health and resigned in October 1916. James Calder, the logical successor, was tainted by the scandal and declined to lead the government. The party turned to William Martin who, as a devout Presbyterian, was expected to heal the rift that developed between Premier Scott and prominent Presbyterians.
The Martin government established several Royal Commissions and dealt decisively with those found guilty of inappropriate behaviour. Martin established and maintained a scandal-free administration. The most notable policies of the new government included granting women the right to vote in provincial elections, reforms of the educational system which required all children between the ages of 7 and 14 to attend an approved school, establishment of a government mortgage-lending organization for farmers, reform of the provincial courts, and passage of a Saskatchewan Bill of Rights which demanded federal tariff reductions and the transfer to the province of Crown lands and resources.
In his first election as Premier in 1917, Martin and his Liberal Party won 50 of the 59 seats in the Legislature. Later that year, Martin endorsed a decision by some federal Liberals to join with the governing Conservatives to form a Union government which was committed to a more aggressive war effort and to the introduction of a policy of military conscription. The Union government also followed tariff and other domestic policies that were not popular in Saskatchewan. That led to the organization of a new western protest party - the Progressive Party of Canada - to represent the interests of farmers. Provincially the Progressives (known as the United Farmers) were elected as minority governments in Ontario and Manitoba, and to a strong majority government in Alberta. Martin and the Saskatchewan Liberals blunted the Progressive appeal by bringing prominent farm leaders into the government, introducing legislation advocated by the Progressives, and calling a provincial election in June 1921 before the provincial Progressives were well organized.
The Liberals won the 1921 provincial election with a large majority, but faced a crisis in the federal election held later in 1921. The federal contest in Saskatchewan pitted Progressives against Liberals in many constituencies. Premier Martin made several speeches in support of Liberal candidates in which he also declared his personal opposition to many of the policies of the Progressives. That led to the resignation of J.A. Maharg, the provincial Minister of Agriculture and a strong supporter of Progressives. The tensions in the Cabinet and caucus culminated in Martin's resignation as Premier at the age of 46. His successor, Charles Dunning, was a former farm leader and enjoyed the support of members who supported the Progressives federally.
William Martin was appointed as a judge in the Saskatchewan Court of Appeal shortly after his resignation as Premier. There he joined Chief Justice Sir Frederick Haultain, the Territorial Premier before 1905. Martin succeeded Haultain as Chief Justice in 1941 and served in that capacity until his retirement in 1961 at the age of 84. During the war, Martin also served as custodian of Enemy Alien Property in Canada, and in 1949 he was chairman of a commission assigned the task of revising the Canadian Criminal Code.