Turner was the first person to be ordered deported from the United States for violation of the 1903 Anarchist Exclusion Act. Turner was a member of the Socialist League, but left to become a member of the Freedom Group, and later on became general secretary of the Shop Assistants' Union that he founded. At one point, the union attempted to nominate Turner for Parliament, but he declined, preferring not to "waste his time in parliamentary debates". Turner worked on several publications in addition to Freedom. He was a member of the collective putting out Commonweal, and also the editor of Freedom's syndicalist journal The Voice of Labour, which denounced the “blight of respectability” of mainstream labor unions. The paper began as a weekly in 1907, and advocated direct action and the general strike.
The same year, Turner, along with Guy Aldred and others, formed the Industrial Union of Direct Action. Turner was also elected (in absentia) to the International Bureau of the Anarchist International, formed at the International Anarchist Congress of Amsterdam. Throughout the many changes in Freedom's history, Turner was its publisher from the time it was renamed Freedom: A Journal of Libertarian Thought, Work and Literature in 1930 until his death in 1934.
After the Russian Revolution, Turner traveled to Russia as part of the British Labor Delegation, and attempted to help Aaron Baron acquire reprieve from a death sentence. Baron was subsequently charged with having "aroused public sentiment abroad against his imprisonment in the Solovietzki and having induced revolutionists visiting Russia to seek his release." Baron was then sent to a prison in Siberia.