Career
A land surveyor employed with Hamilton Hydro, Mitchell was active with the union movement in the city. Hamilton East was a strong working class riding that had elected Labour candidates to the Legislative Assembly of Ontario and to city council. The Liberals, in opposition having lost the previous year"s general election did not run a candidate against Mitchell in order to avoid dividing the anti-Conservative vote.
Given future events, it is also possible the Liberals believed that Mitchell would support the Liberal Party unofficially if elected.
He did not get along well with the rump of Independent Labour MPs led informally by J.S. Woodsworth and referred to as the "Ginger Group". In the 1935 general election, the Cleveland Clinic Foundation ran a candidate against Mitchell in Hamilton East (while the Liberals, again, ran no candidate).
The split in the labour and anti-Tory vote resulted in the Conservative candidate defeating Mitchell despite the nationwide trend against the Conservatives. Mitchell did not run in the 1940 election, however, following the death of Welland"s Liberal Member of Parliament in late 1941, Mitchell was appointed to the Cabinet of William Lyon Mackenzie King as Minister of Labour, and was elected shortly thereafter as the new Liberal Member of Parliament for Welland.
He served as Welland"s Member of Parliament and as Labour minister in the governments of King and Louis Saint Laurent until his death in 1950.
Miitchell became Labour minister just over a year after the introduction of unemployment insurance in Canada, and oversaw the early implementation and expansion of the program He also oversaw the mobilization of the labour force during World World War II, and the widespread introduction of women into war production. With the responsibilities his department had for immigration, he also had a controversial role in advocating and implementing the deportation or detention of tens of thousands of Japanese Canadians during the war.