Irvine was born at Gletness in Shetland, Scotland, one of twelve children in a working-class family. He became a Christian socialist in his youth, and worked as a Methodist lay preacher. He moved to Canada in 1907 after being recruited for ministerial work by James Woodsworth, the father of future CCF leader J. S. Woodsworth. Irvine was a follower of the social gospel, and rejected biblical literalism. He refused to sign the Articles of Faith when ordained as a Methodist minister, claiming that he accepted the ethical but not the supernatural aspects of Christian belief. He was nonetheless accepted into the ministry, and was stationed at Emo, Ontario, in 1914. Irvine was accused of heresy the following year by a church elder, and, although acquitted of the charge, chose to resign his commission. He left the Methodists, and accepted a call to lead the Unitarian Church in Calgary, Alberta in early 1916. In addition to his work as a Unitarian minister, Irvine became politically active after moving to Alberta. He helped establish an Alberta branch of the radical agrarian Non-Partisan League in December 1916, and was an NPL representative at the creation of the Alberta Labor Representation League in April 1917. Irvine himself stood as an LRL candidate in the 1917 provincial election, but was defeated in Calgary. He also founded the Nutcracker newspaper in 1916, and oversaw its later transformations to the Alberta Non-Partisan and the Western Independent.
Political career
First campaigns
He campaigned for the House of Commons of Canada in 1917, as a Labour candidate opposing Robert Borden's Unionist government during the Conscription Crisiselection of 1917. His platform overlapped with that of the Alberta Non-Partisan League. While not a pacifist, Irvine denounced war profiteering and called for the "conscription of wealth" rather than of men. He was accused of holding pro-German sympathies. He was defeated, and he also lost his funding from the American Unitarian Association in Boston. Still supported by his local congregation, he set up his own "People's Church" in Calgary in 1919 as part of the Labour church movement. In the same year, he helped establish the Alberta wing of the Dominion Labor Party. Irvine lived briefly in New Brunswick in 1920, and supported that province's United Farmers movement during a federal by-election. After returning to Calgary, he helped convince the United Farmers of Alberta to enter political life. The UFA had previously been divided between members who supported direct political action, and others such as Henry Wise Wood who wanted to remain an agrarian pressure group. The former position was accepted following a series of public debates between Irvine and Wood at UFA meetings, though Wood was successful in restricting the UFA's membership to farmers. Irvine's first book, Farmers in Politics, endorsed the UFA policies of economic co-operation and group government.
He was first elected to the House of Commons in the 1921 federal election as a Dominion Labour Party candidate in Calgary East. Two other Labour MPs were elected in Canada that year. Irvine became close political and personal friends with Winnipeg North Centre MP J. S. Woodsworth. The two of them launched an investigation into social credit, and even brought social credit theorist Major C.H. Douglas to Ottawa to speak on monetary reform. Irvine was defeated in 1925 when he ran for re-eleciton. He was next elected in 1926, when he ran for the UFA in the rural Alberta riding of Wetaskiwin. Despite the change in his party affiliation, he remained a leading ally of Woodsworth and of farmer-labour co-operation. He, Woodsworth and many Farmer and Labour MPs formed the "Ginger Group", which pushed and prodded the House of Commons to pas pro-labour and pro-farmer legislation. Another of his books, Co-operative Government, was published in 1929. In the late 1920s, Irvine introduced an early bill favouring the abolition of capital punishment in Canada. A meeting at which several radical MPs decided to found a national labour-farmer political party, the Co-operative Commonwealth Federation party, was held in Irvine's parliamentary office. Irvine attended the founding of the CCF in Calgary in 1932 and helped bring the UFA into the CCF in early 1933 and the parliamentary UFA caucus into the CCF for the 1935 election. He was personally defeated, losing to a Social Credit candidate. He attempted to re-enter parliament later that year through a by-election in Assiniboia, Saskatchewan but was defeated by former Saskatchewan Premier James Garfield Gardiner. Although Irvine was never a member of the Social Credit Party, he was interested in social credit monetary theories, believing that monetary reform was an important part of bringing a co-operative commonwealth into effect. Irvine became the Alberta CCF's first president. He returned to parliament in the 1945 election for the British Columbia riding of Cariboo. He served in the CCF caucus for four years, and was defeated in 1949 when the opposition united behind Liberal candidate George Matheson Murray. Irvine made three more attempts to return to parliament, in the 1950s, but was unsuccessful each time.