After graduating from Harvard University with the highest honours and studying two years for the ministry, Hicks joined the Communist Party in 1934. As literary editor of the New Masses, he became one of the party's chief cultural spokesmen. His book The Great Tradition (1933; rev. ed. 1935) evaluated American literature since the Civil War from a Marxist point of view.

Hicks was dismissed from his teaching position at Rensselaer Polytechnic Institute in 1935 and consequently became the centre of a storm of controversy over academic freedom in the United States. In 1939 he broke with the Communists after the Nazi-Soviet pact, explaining his growing dissatisfaction with the party's uncritical endorsement of Soviet policy in a letter to The New Republic magazine. He remained an active writer. Part of the Truth: An Autobiography was published in 1965 and in 1970 was published Literary Horizons, a collection of his book reviews over the preceding 25 years. A collection of his essays, Granville Hicks in the New Masses, edited by J.A. Robbins, was published in 1974.