In 1909, Hill was elected General Secretary of the Boilermakers. He was able to strengthen the union in his first five years by focussing on craft unionism and controlling apprenticeships. During World War I, he articulated some of the concerns of Red Clydeside on the national stage, working to get the Munitions of War Act amended, and becoming increasingly important in the Labour Party. In 1917, he served as President of the Trades Union Congress.[1]
Hill remained General Secretary until 1936, but struggled to maintain the union's bargaining power in the face of the Great Depression.[1]