Pollitt was born 22 November 1890 in Droylsden, Lancashire. He was the second of six children of Samuel Pollitt (1863–1933), a blacksmith's striker, and his wife, Mary Louisa (1868–1939), a cotton spinner, daughter of William Charlesworth, a joiner. Pollitt's parents were socialists and it was his mother, a member of the Independent Labour Party, who provided the youngster with his first induction into the principles and local networks of socialism. She was a member of the Openshaw Socialist Society and regularly took Harry with her to events in their Socialist Hall. Theirs was an especially close relationship and Pollitt found in his mother both a confidante and a model of working-class dignity in the face of affliction.