Iranian cleric who played a key role in establishing Iran as an Islamic republic in 1979. As a Shīʿite religious scholar of some note, he was addressed with the honorific ayatollah.

Beheshti studied with the noted Shīʿite cleric Ayatollah Ruhollah Khomeini (Khomeini, Ruhollah), of whom he would remain a devoted follower. After graduating from a religious school in the city of Qom, he traveled to Europe and in the 1960s served as a mullah to Iranian Muslim students in West Germany. He later returned to Iran and in the early 1970s worked as a religious adviser to the Ministry of Education. Active in anti-shah activities, he became part of Khomeini's opposition network and was imprisoned.

Reputed to be an astute planner, Beheshti helped topple the shah's regime in 1979, bringing Khomeini to power. On February 3, 1979, Khomeini appointed him a member of Iran's Islamic Revolutionary Council, and he soon became the council's first secretary. He also became leader of the newly founded Islamic Republican Party (IRP), which was the most important group in the Majles (parliament). Considered the most powerful man in Iran after Khomeini, Beheshti played a leading part in the U.S. hostage crisis and was instrumental in the dismissal in June 1981 of Abolhasan Bani-Sadr (Bani-Sadr, Abolhasan), the first president of the Islamic republic. There was violent opposition to the new regime, however, and during a meeting at IRP headquarters, Beheshti and a number of other party officials were killed in an explosion allegedly triggered by an antigovernment group, the Mojāhedīn-e Khalq (Persian: “People's Fighters”).