[1] His parents were active in the Co-operative Movement, and as a young man Fox joined the Socialist Party of Great Britain and the Industrial Workers of the World (IWW).
He was abruptly released in April 1919; later that year he authored his first book, Factory Echoes, and enrolled at Ruskin College in Oxford where he studied Economics and Political Science.
He was invited to Soviet Russia in 1921 to observe the results of the recent Russian Revolution, and in 1922 he visited Dublin and established contacts with leading leftist figures there.
[4] Fox was introduced to left-wing circles by Delia Larkin and through her met Alice Stopford Green, Hanna Sheehy-Skeffington, Dorothy Macardle, and Maud Gonne MacBride, with the latter two becoming his lifelong friends.
Fox supported the Irish War of Independence following the death by hunger strike of Terence MacSwiney and subsequent atrocities carried out by the Black and Tans on behalf of the British authorities.
[2] Following his graduation from Ruskin, Fox married Patricia Lynch and they spent time in London, Paris, Brussels, and Germany before eventually settling in Dublin.
[3] Active in literary, dramatic, and left-republican circles, Fox joined the National Union of Journalists (NUJ) and the Irish branch of PEN International in the early 1930s.
In 1956, Fox was invited to visit Maoist China for the centenary of George Bernard Shaw, joining pacifists including Hubert Butler, David William Greene, and Arland Ussher.
He also authored memoirs and historical works: Smoky Crusade (1937) detailed his life up to the early 1920s; Rebel Irishwomen (1935) profiled figures like Sheehy-Skeffington, Eva Gore-Booth, Constance Markievicz, Nora Connolly O'Brien, and Helena Molony; and Green Banners: The Story of the Irish Struggle (1938) presented a popular account of 1916 to 1921, sympathetic to the Irish Citizen Army and anti-Treaty left-republican views.