By redefining the role of the Trades Union Congress (TUC), whose General Secretary he was from 1926 until 1946, he helped create a far more coherent and effective union force. This, in turn, transformed the Labour Party into a substantial social democratic force for government from 1939. Citrine was also President of the then influential International Federation of Trade Unions (IFTU) from 1928 until 1945. He was also joint Secretary of the key TUC/ Labour Party National Joint Council from 1931 and a director of the UK Daily Herald newspaper until 1946 which was then a mass circulation Labour paper with considerable influence. In these important roles, Citrine was highly influential in the industrial and political wings of the labour movement. His prominent involvement helped secure its recovery after the deep crisis and crushing defeat which followed the fall of the British Labour government in 1931. In particular, he played a key role from the mid-1930s in reshaping Labour's foreign policy, especially as regards re-armament and through the all-party anti-Nazi Council in which he worked with Winston Churchill.