He is notable as being one of the founders of the National Front (Iran), a group of politically active Iranians who wished to rid Iran of foreign domination and introduce a parliamentary and democratic political system into the country. Sanjabi was a loyal supporter of Mohammad Mossadegh (the charismatic leader of the nationalists) and he later served as minister of education under Mossadegh (who became prime minister in April, 1951) in 1952. Mossadegh had lead the movement to nationalize the British-controlled oil industry in Iran (which, after nationalization, became known as the National Iranian Oil Company) and after this was accomplished, he became engaged in a heated battle with the British (who had previously controlled the oil industry and wished to reassert control over it) and with the forces rallying around Mohammad Reza Shah (the king of Iran who was opposed to Mossadegh's policies vis a vis the British, as well as the prime minister's efforts at limiting the Shah's power and influence). After a CIA-MI6 coup'etat overthrew Mossadegh in Aug. 1953 and re-established the Shah on the throne, Sanjabi became a prominent opponent of the Shah's dictatorial rule.
As the leader of the National Front during the revolutionary uprising of 1978-1979, Sanjabi and his colleagues initially wished to negotiate a peaceful solution with the Shah, but in November 1978, he declared his support for Ayatollah Ruhollah Khomeini, who at the time was extremely popular amongst the religious masses. After the overthrow of the Monarchy on February 11, 1979, Sanjabi served as the foreign minister of the new Islamic Republic for a brief period until April 1979. After this, he became an opponent of Khomeini's regime and he fled Iran in 1982. He died in 1995.