Hallworth grew up in Stockport, and worked in a cotton mill from an early age.
In 1914, aged 16, he joined the Royal Fusiliers as a drummer and served throughout World War I.
He was demobbed in 1919, and began working for the London, Midland and Scottish Railway as an engine cleaner.
He was subsequently promoted to become a fireman, then a spare driver, and joined the Associated Society of Locomotive Engineers and Firemen (ASLEF).
In 1955, he helped organise a major railway strike, and that year also won a seat on the General Council of the Trades Union Congress.