In 1919, Midgley joined the Belfast Labour Party, and in 1920 he was elected to Belfast City Council. At the time of the 1921 Northern Ireland general election, the first ever election to Northern Ireland's embryonic parliament, the "principal anxiety" of James Craig was that Labour in Belfast would attract the loyalist vote. When Labour candidates booked the Ulster Hall for a final rally, it was disrupted by Loyalist shipyard workers, who then telegraphed Craig to inform him that they had "captured the Ulster Hall from Bolsheviks Baird, Midgley and Hanna". Craig responded: "...Well done big and wee yards". Midgley was indeed defeated in his attempt to win the Belfast East seat. In the 1923 UK general election, Midgley won 47% of the vote, the best result for the Labour movement in Northern Ireland until the 1943 Belfast West by-election. His vote dropped slightly in the 1924 UK general election, but held his council seat until 1943, becoming an Alderman in 1929. In the 1933 Northern Ireland general election, Midgley was elected for Belfast Dock, by now representing the Northern Ireland Labour Party which the Belfast Labour Party had formed. He also joined the board of Linfield F.C.. Following his election, he became the party leader. During the Spanish Civil War in the late 1930s, Midgley was outspoken in his support for the beleaguered Spanish Republic and described Franco as a "monstrosity" and a "killer of babies". In turn, Midgley became involved in a public controversy regarding The Irish News' attitude to the Spanish Civil War. The newspaper supported Francisco Franco's Nationalists, partly because of Spanish Republican anti-clericalism, while Midgley saw the Spanish Republican side as fighting a necessary war against fascism and for democracy. When the 1938 election was called, Midgley's opposition to Franco was to cost him dearly. The Nationalist Party stood a candidate against him, Mr James Collins, who supported Franco's armed rebellion. During the election campaign, "ight after night there were violent clashes in the Dock constituency as Midgley faced hostile crowds shouting 'Up Franco', 'Remember Spain', and 'We want Franco'". Midgley was also opposed by a Unionist candidate, to whom he lost his seat.
Later career
Midgley won the Belfast Willowfield constituency in a 1941 by-election for the NILP. His victory in this strongly loyalist seat left John Miller Andrews, then Prime Minister of Northern Ireland, severely shaken. The Prime Minister later confided to Wilfrid Spender that "if there was a general election now the government would cease to have a majority". Midgley resigned from the NILP the following year in protest at Jack Beattie's leadership. Intending to work constructively with the Ulster Unionist Party, who dominated politics in Northern Ireland, Midgley formed the Commonwealth Labour Party. When Basil Brooke became Prime Minister of Northern Ireland in May 1943, he replaced all but one member of the existing cabinet and appointed Midgley as Minister of Public Security. Midgley also became a member of the Privy Council of Northern Ireland. The following year, he became Minister of Labour. In the 1945 Northern Ireland general election, Midgley was the Commonwealth Labour Party's only successful candidate, while in the 1945 UK general election, he won 30% of the vote in Belfast South against Ulster Unionist opposition. On 30 October 1945 Midgley protested when the Speaker, Sir Norman Stronge, agreed to Jack Beattie's request to examine a ruling he had given. Midgley shouted at Stronge "Are you not competent to discharge your duties without advice from this Member on his weekly visits to the House?" Despite Stronge calling for order, Midgley then crossed over and punched Beattie. Stronge excluded him from the Chamber for the rest of the sitting and Midgley apologised the next day. Growing closer to the Unionists, Midgley disbanded his party and joined the UUP in 1947. He became Minister of Labour and National Insurance in 1949 and then Minister of Education in 1950. Midgley's outspoken Unionism did not diminish over the years. In Portadown, in 1957, he said, "All the minority are traitors and have always been traitors to the government of Northern Ireland". Midgley died, while still in office, later that year.
