His ouster also ended the 2,500 years of continuous monarchy in the country.
The revolution gained momentum as all opposition forces rallied behind the Imam Khomeini, the Islamic world spiritual and religious leader.
Imam was sent into exile by the Shah regime and spent over 14 years in exile. He had constantly been monitoring the Islamic movement and issuing recommendations from abroad during this period.
As the protests against the Shah regime increased, the Shah left and fled the country in January 1979.
On February 1, 1979, Imam Khomeini returned from his exile in France and was welcomed by millions of people.
In a last ditch effort to save the monarchy, the Shah appointed Shahpour Bakhtiyar as the prime minister.
But on 11 February, just five weeks into his tenure, he was forced to abandon his power as revolution reached its peak.
Immediately, Imam Khomeini formed a revolutionary council and appointed Mahdi Bazargan as the prime minister of a provisional government.
Imam Khomeini also directed relevant authorities to conduct a referendum to seek people's approval. On 31 March, 1979, 97 percent of the voters voted in favor of the Islamic Republic.
In December of the same year, the country also got its new constitution.
US-backed western powers were caught by surprise due to rapid pace with which the revolution took place.
Experts maintain that there were historical reasons for the eventual overthrow of the Shah.
Given his penchant for westernisation and his perceived closeness to the United States, the Shah came to be considered an "American puppet."
In fact, it was the US which, with the help of the UK, propelled the Shah back to power by overthrowing the popularly-elected Mohammad Mosaddegh.
This intervention created a poor impression of the West among Iranians.
Shah's 1963 White Revolution, which attempted to Westernized the country, angered public masses led by Imam.
Critics also pointed out that the benefits of the so-called modernization process by Shah regime never reached the villages and the lower strata of the society.
in 1971, Shah celebrated the 2,500th year of monarchy even as the opposition against his policies was growing.
Analysts believe that Imam Khomeini’s divine personality played a main role in leading the historic revolution to victory in 1979.
The Islamic Revolution changed the balance of powers in the interest of oppressed nations.