Despite being a federal Member of Parliament and not yet an MLA, Douglas was elected the leader of the Saskatchewan CCF in 1942 after successfully challenging the incumbent leader, George Hara Williams, but did not resign from the House of Commons until 1 June 1944. He led the CCF to power in the 1944 provincial election, winning 47 of 53 seats in the Legislative Assembly of Saskatchewan, and thus forming the first social democratic government in not only Canada, but all of North America. As premier, Douglas attended the coronation of Queen Elizabeth II in June 1953.