William Proudfoot (1859-1922) was an Ontario politician and barrister. In 1908 he was elected to the Legislative Assembly of Ontario as a Liberal. He was re-elected in 1911 and 1914. In 1917, he was chosen leader of the Liberal Party and, as such, became Leader of the Opposition in the legislature. The 1919 election saw the Liberals and their allies drop from 30 seats to 27 with Proudfoot, himself, being defeated in his riding of Huron Centre by the Labour candidate. No longer having a seat in the legislature, Proudfoot was challenged as Liberal leader at the party's first leadership convention and was replaced by Hartley Dewart. He then became a member of the Senate of Canada where he sat until his death in 1922.
