In 1971 Chamran left the US for Lebanon and joined the camps of the Palestine Liberation Organization and the Amal movement. He became a leading and founding member of the Islamic revolutionary movement in the Middle East, organizing and training guerrillas and revolutionary forces in Algeria, Egypt, Syria. During the civil war in Lebanon he actively cooperated with Musa Al Sadr, founder of the Amal movement. Chamran also became an Amal member and "right-hand man of Sadr".