former playboy has been so tainted by graft allegations over two decades in politics that he retains the nickname "Mr Ten Percent".
He will go down in history as the head of state who abrogated sweeping powers as part of an electoral promise to restore the parliamentary constitution his father-in-law introduced in 1973.
The 18th amendment to be signed on Monday rolls back four decades of infringements by military rulers on the constitution.
The amendment will strip Pakistan's 14th president of the power to dismiss governments and appoint leaders of the powerful military, and may go some way to easing political tensions that have simmered since he took office.
Zardari's colourful past, which included 11 years in jail on charges ranging from corruption to murder, came back to haunt him in December when the Supreme Court scrapped a controversial amnesty that sparked calls for his resignation.
Although Zardari has immunity against prosecution as long as he remains in office, his government has come under pressure to reopen money-laundering cases in Switzerland involving millions of dollars and shelved in August 2008.
By invalidating the National Reconciliation Ordinance imposed by former military ruler Pervez Musharraf in 2007, the Supreme Court also opened the door to any possible petitions challenging the 54-year-old's immunity at home.
Zardari's life journey has taken him from playboy to villain to political heir of the revered Bhutto, whose image still casts a shadow over daily life nearly three years after her assassination in a gun and suicide attack.
Born on July 26, 1955 into a land-owning, polo-playing family from southern province Sindh, Zardari was educated in Pakistan and went on to study business in London, although he never graduated from university.
Little known at the time of his arranged marriage into the Bhutto dynasty in 1987, he quickly carved out a powerful position for himself, serving as a government minister under his wife's two administrations.
Although he has never been jailed by a court and says all charges against him were politically motivated, in 1990 he went to prison for three years before rejoining Bhutto's second administration.
He was back behind bars within half an hour of its dismissal in 1996.
Zardari then spent eight years in jail -- five of them while his family lived in exile -- before being freed in November 2004 after being cleared over the last of 17 cases of corruption, murder and drug smuggling.
In October 2007, his wife returned from self-imposed exile from Dubai. Two months later, she was killed in an attack on a political rally in Rawalpindi while Zardari was still living abroad.
Her assassination stunned the world, plunged Pakistan into mourning and propelled Zardari out of the shadows of notoriety into the political limelight.
Kept at bay for years by his wife's Pakistan People's Party (PPP), uncomfortable with his shady reputation, Zardari took control as co-chairman alongside his then teenage son who is still a student at Oxford.
The PPP unanimously supported Zardari's candidacy for president after winning the 2008 election, at least partly in tribute to the sacrifices of his wife and he took power only nine months after her assassination.
After assuming office in September 2008, Zardari's government rapidly came under fire over expanding Islamist militancy and economic turmoil, sending his approval ratings plummeting.
His administration has however seen a marked rapprochement with the United States, which has praised the military operations and passed a massive 7.5 billion dollar civilian aid bill to Pakistan.