An event that helped pass the constitution, radicalize the revolution and strengthen its anti-American stance, was the Iran hostage crisis. On November 4, 1979, a group of Iranian students seized the U.S. embassy in Tehran holding 52 embassy employees hostage for 444 days. The Carter administration severed diplomatic relations and imposed economic sanctions on April 7, 1980, and later that month unsuccessfully attempted a rescue that further enhanced Khomeini’s prestige in Iran. On May 24 the International Court of Justice called for the hostages to be released. Finally, the hostages were released 20 January 1981, by agreement of the Carter Administration of Algiers Accords Jan. 19, 1981. The crisis also marked the beginning of American legal action, or sanctions, that economically separated Iran from America. Sanctions blocked all property within US jurisdiction owned by the Central Bank and Government of Iran.

The eight-year-long Iran–Iraq War (September 1980 – August 1988, known as The Imposed War in Iran) was the most important international event for the first decade of the Islamic Republic and possibly for its history so far. It helped to strengthen the revolution although it cost Iran much in lives and treasure.

The leader of the revolution and founder of the Islamic Republic, Ayatollah Ruhollah Khomeini, was Iran’s supreme leader until his death in 1989 and was followed by Ayatollah Ali Khamenei.