After serving on the Western Front in the Great War, he became an official in a textile workers union and a leading light in the Belfast Labour Party (BLP).
He represented the party's efforts in the early 1920s to provide a left opposition to the Unionist government of the new Northern Ireland while remaining non-committal on the divisive question of Irish partition.
He left school at age twelve, and worked two years as a grocer's helper before following his father (who died when Midgley was just six) into the Workman & Clark shipyard apprenticing as a joiner.
Midgley highlighted the plight of unemployed ex-servicemen, hailed the revolutionary workers' uprisings in Russia and Germany, and urged municipalisation of distribution of essential commodities.
When the expulsion of catholic workers from the shipyards by loyalist mobs was followed by similar attacks on leftist Protestants in July 1920, Midgley was among the trade-union leaders targeted for abuse.
In the absence of the nationalist Joseph Devlin, who was boycotting the northern parliament, Midgley won 47% of the vote, narrowly losing to the incumbent Unionist.
In the constituency's Protestant ward of Shankhill Midgley emphasised his loyal wartime military service, while in the Catholic Falls area he attacked the policy of internment directed at Irish republicans.
[9] In 1925 he was returned to the Belfast City Council for Dock Ward on a platform that called for new housing and rent restrictions, and for free education.
[8]: 544 In turn, Midgley became involved in a public controversy regarding The Irish News' attitude to the Spanish Civil War.
[13] Contesting the Dock constituency in the 1938 Northern Ireland election Midgley saw nationalist protest against his support for the Spanish Republic reduce his vote share to 24%.
[3] His victory in this strongly loyalist seat left J. M. Andrews, then Prime Minister of Northern Ireland, severely shaken.
[8] But for many within his own party, Midgley's willingness to "evangelise about the Union ran the risk of appearing to steal Unionists' clothes and was difficult to square with the oppositional role Labour occupied".
[19] In policy statement issued by the new party in January 1943, the CWLR committed itself to the consolidation of Northern Ireland within the United Kingdom and the British Commonwealth, and to the attainment of a system of social security and justice at par with the Labour's programme for Great Britain.
The CWLR also adopted Clause Four of the British party's 1918 constitution:[20] To secure for the workers by hand or by brain the full fruits of their industry and the most equitable distribution thereof that may be possible upon the basis of the common ownership of the means of production, distribution and exchange, and the best obtainable system of popular administration and control of each industry or service.
It represented a sufficiently significant development that when in May 1943, Basil Brooke wished to broaden the base of government and distinguish himself from the leadership of Andrews, discredited in the wake of the Belfast Blitz, he appointed Midgley as Minister of Public Security.
[23] The first non-UUP Stormont minister, Midgley, who could present himself as one of the many thousands in Belfast who had lost their home to German bombs, tirelessly toured Northern Ireland working to maintain civilian morale and civil defence readiness.
Concerned that immigrants from the south would "gravitate to the disloyal element in our population", he enacted a policy of granting the necessary residence permits only when warranted by the labour situation.
In the UK general election later that year, he was held at 30% of the vote in Belfast South by a hardening Ulster Unionist opposition.
Midgley appealed to his Protestant working-class base by calling for a withdrawal of state support for Catholic schools on the "socialist" principle that child education should comprehensive and nondenominational.