In 1946 he was convicted of burglary and sentenced to ten years imprisonment. While in prison he was converted to the Black Muslim faith.

After his release from prison in 1952 he moved to Chicago where he met Elijah Muhammad, leader of the Nation of Islam sect. He changed his name to X, a custom among Muhammad's followers who considered their family names to have originated with white slaveholders.

Malcolm soon became a leading figure in the Nation of Islam. He went on several speaking tours and helped establish several new mosques. He was eventually assigned to be minister of the mosque in New York's Harlem area. Founder and editor of Muhammad Speaks, Malcolm rejected integration and racial equality and instead advocated black power.