Ali Akbar Hashemi Rafsanjani has been a dominant figure in Iranian politics since the 1980s.
Described as a "pragmatic conservative", he is part of the religious establishment, but he is open to a broader range of views and has been more reflective on relations with the West.
Mr Rafsanjani was president for eight years from 1987 and ran again in 2005. He lost to Mahmoud Ahmadinejad in the second round. He has been openly critical of the president since then.
He is still a powerful figure in Iranian politics as he heads two of the regime's most powerful bodies: the Expediency Council (which adjudicates disputes over legislation) and the Assembly of Experts (which appoints, and can theoretically replace, the Supreme Leader).
In the 2009 election he was a prominent backer of Mir Hossein Mousavi who contested the result that gave Mr Ahmadinejad a second term.
He has close links to Iranian industry and business and is considered to be the richest man in Iran. He was featured in the Millionaire Mullahs section of the Forbes Rich List in 2003.
There have been persistent accusations that he amassed a personal fortune thanks to his political connections - allegations that he has always denied.
Born in 1934 in south-eastern Iran to a family of farmers, he studied theology in the holy city of Qom with Ayatollah Khomeini, whose close follower he became. He was imprisoned several times under the Shah.
Mr Rafsanjani was speaker in the Majlis (Iran's parliament) from 1980-89. In the last year of the 1980-88 war with Iraq, Ayatollah Khomeini appointed him acting commander-in-chief of the armed forces.
He is seen as the main mover behind Iran's acceptance of the UN Security Council resolution which ended the war.
As president, Mr Rafsanjani sought to encourage a rapprochement with the West and re-establish Iran as a regional power.
His influence in Lebanon helped to bring about the release of Western hostages there in the early 1990s.
Domestically, he pursued an economically liberal policy that critics said failed to deliver on social justice.
However, he opposed harsh Islamic penal codes and promoted better job prospects for women.
His financial policies aimed to move Iran from the state-controlled economy of the Iran-Iraq war years to a more market-based system.
In recent years he has condemned Mr Ahmadinejad's economic policies, accusing them of having seriously damaged Iran.
On the nuclear issue, he was in favour of negotiation with the West, but "not to accept bullying and imposition".
Indeed he warned Washington that its "threats" are futile.
In 2007, at Friday prayers, he spoke out against nuclear weapons and said he was disappointed that the US, which still has a nuclear arsenal, was trying to stop Iran from using nuclear energy for peaceful purposes.
In 2002, Mr Rafsanjani was appointed head of the powerful Expediency Council, which arbitrates in disputes between the Majlis and the Guardian Council, which can block legislation.
In 2006, he was elected to the Assembly of Experts and a year later was voted leader of the body which appoints the supreme leader.
Hardliners within the Assembly of Experts were strongly opposed to Mr Rafsanjani's bid to remain as leader in elections in January 2009. He stood against Ayatollah Mohammad Taghi Mesbah Yazdi who is a supporter of President Ahmadinejad and won a convincing majority.
He was a prominent backer of Mr Mousavi in the 2009 presidential elections when he stood against President Ahmadinejad.
The relationship between Mr Rafsanjani and President Ahmadinejad has come under further strain since campaigning for the 2009 election began.
Mr Ahmadinejad accused Mr Mousavi of being supported by corrupt politicians, and named Mr Rafsanjani.
Mr Rafsanjani penned a public letter to Ayatollah Khamenei, appearing blaming the Supreme Leader for remaining silent in the face of such accusations.
"If the system cannot or does not want to confront such ugly and sin-infected phenomena as insults, lies and false allegations made in that debate, how can we consider ourselves followers of the sacred Islamic system," he wrote in a rare public rebuke.