Born in 1947 in a Shi’ite holy city of Karbala, south of Baghdad, al-Ja'fari joined the Islamist Al-Dawah Party in the 1960s. In the 1970s, Al-Dawah fought a bloody campaign against Iraqi leader Saddam Hussein's regime, during which many were killed or forced to leave the country.
"He was very active in Iraq, he was jailed, and he fled Iraq in the 1980s," said Kamran al-Karadaghi, an Iraq expert at the Institute for War and Peace Reporting in London. "He went to Iran, then he left Iran and settled in London for the last maybe seven years."
Many Iraq observers say it will be difficult to predict how al-Ja’fari might act as prime minister. That is partly because he is a difficult figure to characterize politically or ideologically.
During his years in exile, al-Ja’fari strongly opposed Saddam Hussein but never publicly supported an Iranian-style theocracy.
"People who know him for example say that he doesn't support this concept of Vilayat-i Faqih (Governance of the Jurist), but he never says this publicly," al-Karadaghi said. "There is a kind of vagueness about it."
Karadaghi said that many politicians in Iraq think al-Ja’fari is not as modern as he seems and fear that he might try to push for a greater role for religion in the country.
In the elections, the Islamist Al-Dawah Party ran as one of the main players on the broad Shi’a list, the United Iraqi Alliance, with the backing of Grand Ayatollah Ali al-Sistani.
However, al-Karadaghi pointed, al-Ja’fari was one of the first Iraqi Shi’ites who cooperated with the United States before and after the toppling of Saddam Hussein.
Al-Ja’fari held the largely ceremonial post of vice president in the U.S.-led caretaker government and was a member of the now defunct U.S.-appointed interim Governing Council. Also, al-Ja’fari has not called for the withdrawal of U.S. troops from Iraq.
Although hard to characterize, analysts said al-Ja’fari is a skilled political player who has the ability to unite the fractious country.
Many Iraq watchers said that al-Ja’fari is one of several Shi’ite politicians who command wide respect among Iraq’s alienated Sunni Arab minority.
Al-Ja’fari pledged yesterday that, if elected, his government would be inclusive and would do everything to unite Iraq.
"We want to have ministers of both genders, men and women," al-Ja'fari said. "We want to have Arabs along with Kurds, Turkomans, etc., [representatives] of all colors. I think that if the cabinet focuses essentially on the matter of quality and if it takes into consideration the diversity [of society] it will succeed in its work."
Julian Lindley-French, a Geneva-based security analyst, said al-Ja’fari is the best candidate for prime minister.
"He's the candidate that is most likely to ensure that all three major groupings are prepared to do some pragmatic work on the new constitution," French said.
French said that al-Ja’fari has the chance to keep "some degree of order" and move the country out of the situation it is in now.
However, Yahia Said, a researcher specializing in Iraq and other transitional nations at the London School of Economics, said al-Ja'fari would have a difficult job.
"He will have a lot of challenges ahead of him," Said said. "Especially dealing with the fractious parliament, groups such as Kurds and groups associated with [outgoing interim Prime Minister Iyad] Allawi, who will probably resist his policy proposals."
Whether al-Ja’fari is to be a long-term fixture of Iraqi politics is still unclear. Some observers have pointed out that al-Ja’fari still has not settled in Iraq. His wife and five children remain in London, and the likely prime minister is said to be staying at a friend's house.