Seyyed Mir-Hossein Mousavi was born on 2 March 1942 in Khameneh, East Azerbaijan, Iran. He is an ethnic Azerbaijani, whose family originated from Tabriz. His father, Mir-Ismail, was a tea merchant from Tabriz. Mousavi grew up in Khameneh, and moved to Tehran following his graduation from high school in 1958. Mousavi is a relative of fellow Khameneh native Ali Khamenei: Mousavi’s grandmother is Khamenei’s paternal aunt.

He earned his undergraduate degree in architecture from the National University of Tehran (now Shahid Beheshti University), and in 1969 was awarded his master’s degree in architecture from the National University of Tehran, focusing primarily on traditional Iranian architecture. While a student, he was an active member of the leftist Islamic association of students. During his college years, Mousavi had a close relationship with the Freedom Movement of Iran, a religious-nationalist political party founded by Ali Shariati, whom Mousavi admired for many years. Although the party would not be invited to the post-revolution government, many future political leaders of Iran who were affiliated with the party at the time, among them Mehdi Bazargan, Yadolah Sahabi, Mahmoud Taleghani, and Mostafa Chamran would become Mousavi’s closest allies. Mousavi was among the student activists who regularly attended Ali Shariati’s lectures at Hosseiniyeh Ershad of Tehran, where Mousavi also exhibited his artwork under the pseudonym Hossein Rah’jo.

In 1969, Mousavi married Zahra Rahnavard, a fellow university student who specialized in sculpture, and was among the well-known students of Ali Shariati. Rahnavard later became the Chancellor of Alzahra University as well as political adviser to Iran’s former President Mohammad Khatami. The couple have three daughters; all speak Azeri, Persian, English, and Arabic.

Following the collapse of the Shah’s regime in 1979, Mousavi helped Mohammad Beheshti found the Islamic Republican Party in 1979 in order to assist the establishment of the Islamic Republic in Iran and hasten the overthrow of Iran’s monarchy. He became the political secretary of the party, and chief editor of Jomhouri-e Eslami, the party’s official newspaper. For this, he is widely viewed as “The Architect” of the Islamic Republic both in Iran and abroad.

In mid-1979, he was appointed by Khomeini to the Iranian Council of Islamic revolution. As the chief editor of Jomhouri-e Eslami, he was a loud critic and opponent of Abolhassan Banisadr, the first president of the Islamic Republic, until the latter’s 1981 flight to France, following a successful impeachment by parliament. During Banisadr’s presidency, the prime minister Mohammad Ali Rajai nominated Mousavi as his foreign minister, however Banisadr opposed the nomination and Mousavi was not appointed. On 15 August 1981, as part of the restructuring of the government in Rajai’s cabinet, Mousavi was appointed foreign minister. He held the post until 15 December 1981, when he received the higher appointment of prime minister.

In August 1981, President Mohammad-Ali Rajai and Prime Minister Mohammad-Javad Bahonar were assassinated in an explosion. Ali Khamenei was then elected as the third president of Iran in the October 1981 Iranian presidential election. He put forward Ali Akbar Velayati as his prime minister, but the Iranian parliament did not give him the vote of confidence, and he was defeated with a vote of 80 to 74. Although Khamenei had strong reservations with Mousavi, as a compromise with the left-leaning parliament, agreed to offer Mousavi for the post of premier. On 28 October 1981, with the approval of Khomeini, the parliament approved Mousavi with a vote of 115 to 39 to become the 79th prime minister of Iran on 31 October 1981.

Mousavi’s premiership coincided with the Iran–Iraq War. He guided the country through its war with Iraq, and earned popular acclaim for his stewardship of the national economy. He pioneered a bond-based economy, which many believe was responsible for a fair distribution of goods among the people throughout the Iran–Iraq War. Many analysts praise his handling of Iran’s economy, his civil and economic leadership during the Iran–Iraq War, and his efforts to end Iran’s international isolation. Others remember him as being “unpredictable” and less able to navigate Iran’s labyrinthine political system than were his rivals. In 1986, Mousavi played a great role in the Iran–Contra affair and secret negotiations and dealing with USA on helping them free the American hostages in Lebanon, in return for sale of the American weapons and spare-parts that Iran’s army badly needed for the Iran–Iraq War.

The conflicts between Mousavi, who belonged to the left wing of the Islamic Republic, with Ali Khamenei (the current leader of Iran), who belonged to the right wing of the Islamic Republic, continued during their eight years of shared governance. However, an escalation in conflicts between the two led to Mousavi’s resignation shortly after the end of the Iran–Iraq War in 1988. As the prime minister, Mousavi had the full backing of Ruhollah Khomeini, the supreme leader, and he refused to accept his resignation. While his government was viewed as somewhat liberal, he was still under the pressure of hardliners, though Khomeini generally protected Mousavi from the conservatives and gave him a free rein in deciding actions for the economy. However, his involvement in security matters remained less clear, and it was disputed whether or not Mousavi was involved in the killing of thousands of dissidents and minorities in Kurdistan and Mazandaran during this time. It has generally been accepted that Mousavi and Mohsen Rezaee (who was in charge of the Revolutionary Guards during this time) have never been close, though he was in charge of foreign operations, particularly in Lebanon.

A year after the end of the Iran–Iraq War on 20 August 1988, Ruhollah Khomeini died (June 3, 1989), and Ali Khamenei was elected as the new Supreme Leader by the Assembly of Experts. Following his death, Mousavi and his fellow left-wingers lost their main source of support within the establishment. During the parliament hearing on post-war reconstruction plans, Mousavi had heated arguments with Ali Akbar Hashemi Rafsanjani, the speaker of Iran’s parliament at the time, over Rafsanjani’s suggestion that Iran accept the offer of western countries to help with post-war reconstruction.

On 28 July 1989, the constitution was amended and approved by Iranian voters in a national referendum with a 97% yes vote. At this time, Mehdi Karrubi had been elected as the new speaker of the parliament, to whom the amended constitution was declared. One of these amendments abolished the position of Prime Minister. Rafsanjani was elected as the fourth president of Iran on 28 July 1989, and became the president on 3 August 1989. Mousavi’s premiership ended on the same date. Mousavi was not invited to be a participant in the new government headed by Rafsanjani, and disappeared from the public sphere.

When Khomeini, the founder of the Islamic Republic, died in 1989, Mousavi was no longer welcome in the government. It was the start of 20 years of an almost total absence from public life for Mousavi, which many considered as a sign of his disapproval of the established government, though he did sit on two high-level government councils.

In 1989, Ali Khamenei named him as a member of the Expediency Discernment Council, his membership of which still continues. Mousavi has been a member of the Supreme Council of Cultural Revolution since 1996. He was also the political adviser of president Hashemi Rafsanjani (1989–1997) and senior adviser of president Khatami (1997–2005).

Mousavi refused to run for the presidency in the 1997 elections, which caused the reformists to turn to his former Cabinet Minister, then a little-known cleric, Mohammad Khatami, who was elected by a landslide. During Khatami’s administration, Mousavi served as the Senior Adviser to the President.

Mousavi was considered the leading candidate from the reformist alliance to run in the 2005 Iranian presidential election. However, on 12 October 2004, he officially declined the proposal after a meeting with President Mohammad Khatami and the two other top members of one of Iran’s main Reformist parties, the Association of Combatant Clerics, Mehdi Karroubi and Mohammad Mousavi-Khoiniha.

After 20 years of political silence, on 9 March 2009, Mousavi announced his intention to run in the 2009 Iranian presidential election. He stated that his main goals were: to institutionalize social justice, equality and fairness, freedom of expression, to root out corruption and to speed up Iran’s stagnant process of privatization, and thus move Iran away from what he called “an alms-based economy”. Mousavi criticized the then-current conservative President, Mahmoud Ahmadinejad, for his alleged economic mismanagement, asking, when Iran “was making profits from the high prices of oil, did he (Ahmadinejad) envisage a situation when the prices would fall?” On 16 March 2009, the former Iranian President Khatami withdrew from the election in support of Mir-Hossein Mousavi.

The election was held on 12 June 2009. The official results showed Ahmadinejad winning by a landslide, though Mousavi and many others believed the results to be fraudulent, suggesting that the Interior Minister, Sadegh Mahsouli, an ally of Ahmadinejad, interfered with the election and distorted the votes to keep Ahmadinejad in power. Mousavi has claimed victory, and called for his supporters to celebrate it, sparking large protests as a result.

Seyed Ali Mousavi was the nephew of Mousavi. Ali Mousavi died on 27 December 2009, during the 2009 Iranian election protests, when he was reportedly shot in either the back or the chest by security forces during demonstrations against Mahmoud Ahmadinejad’s contested election win.

In the wake of the Tunisian and Egyptian revolutions, Green movement leaders in Iran called for demonstrations on 14 February 2011. The government responded by placing leaders of the movement under house arrest, and on 14 February Iranian state TV broadcast images of “some 50 conservative MPs marching through parliament’s main hall” chanting “Death to Mousavi, death to Karroubi”.

Mousavi and his wife, as well as Mehdi Karoubi, another opposition figure, were put under house arrest after they urged their supporters to organize demonstrations in support of uprisings in the Arab world in February 2011. On 2 February 2013, Iran’s security forces arrested Mousavi’s two daughters, Zahra and Nargess Mousavi, in their home. The semi-official news agency ILNA reported that they were questioned, and then freed the same day. After the election of Hassan Rouhani as President in 2013, it was announced that Mousavi and Rahnavard would soon be freed from house arrest.

On 12 December 2018 Amnesty International published an interview of the Austrian national public service ORF (broadcaster), on 13 December 1988, with Mir Hossein Mousavi. Mousavi was asked about the mass executions inside Iran’s prison at the time he was in office. Mousave replied,“We repressed them”

In 2019, Mousavi was given the right to exit his home once a week. In addition, his immediate family were also able to visit him anytime. They were also given permission to use a mobile phone and satellite television.