Alfred Short began his working life apprenticed to a boiler-maker at 5s. a week. He rose to become Secretary of the Sheffield Branch of the Boiler-Makers' Society from 1911 to 1919, and serve on Sheffield City Council from 1913 to 1919. He was also Secretary of the National Union of Docks, Wharves and Shipping Staffs. Elected an MP in 1918, Short continued other political activity: in 1922 he was chairman of the Management Committee of the General Federation of Trade Unions, and he was called to the Bar from Gray's Inn in 1923. He was Under-Secretary of State for the Home Department from 1929 to 1931. From 1931 to 1935, when he was out of the House of Commons, he worked for the Transport and General Workers' Union.