A master of the power game, he exploited the West's strategic fears during the Cold War and gave his sprawling and chaotic country at the heart of Africa a badly-needed focus in the turbulent aftermath of independence from Belgium in 1960.
A reluctant convert to democracy, he started pushing, in public at least, for much-delayed multi-party presidential elections - confident that his support in rural areas would enable him to legitimise his rule through the ballot box.
"The democratic process must inevitably be crowned by free and fair elections," he said in a 1996 New Year address.
"I am perhaps the only dictator in the world who is calling for such elections," he once told a television interviewer.
But prostate cancer and a Tutsi-dominated revolt intervened, weakening his grip on the mineral-rich nation of 40 million people.
As Laurent Kabila's rebels have advanced from the east, capturing towns and territory, Mr Mobutu's popularity faded.
Ordinary Zaireans, weary of the ravages of his notoriously ill-disciplined army, poverty and widespread official corruption, have welcomed the rebels as liberators. Mr Kabila insisted he must quit. "There can be no ceasefire or indeed elections in this country until Mobutu and all he represents is removed and thrown away," he said.
President Mobutu offered to resign and hand over to an elected successor, but Mr Kabila is insisting that power be transferred to his rebel alliance in the transition process.
The son of a cook and a hotel maid, Mr Mobutu, who stands 6ft tall, was born in Lisala, in Equateur province in 1930. Denounced as everything from a dictator to a thief, his critics accuse him of ruining what is potentially Africa's richest nation with a wealth of minerals and rich farmland.
A journalist turned soldier, he seized power in 1965 after the old Belgian Congo descended into chaos after independence. Adopting a leopard-skin cap and bird-handled ebony cane as his trademarks, he has held onto power by keeping rivals in disarray, or by buying off his enemies.
He amassed a personal fortune and solidified his grip on the country with a system of economic and political patronage that made millionaires of his close associates. Most Zaireans remained mired in poverty. The word "kleptocracy", meaning a bureaucracy in which corruption is endemic, was coined with Zaire in mind.
Despite human rights abuses and his use of his position to enrich himself, Mr Mobutu became the darling of the United States and others in the West as a buffer against the Communist bloc. Washington relied on Zaire as a supply route for the US-backed National Union for the Total Independence of Angola (Unita) rebel movement fighting a 17-year guerrilla war against the Marxist government of neighbouring Angola.
President Mobutu's usefulness to Washington faded as Soviet influence declined in Africa and Communism finally collapsed. His erstwhile friends began to look more closely at his human rights record.
Under pressure to make reforms, the Zairean leader opened a Pandora's box, when he permitted multi-party politics in April 1990 after more than two decades of single- party rule. At the same time, the mineral-based economy collapsed as production from vital copper mines in the south plummeted.
Mr Mobutu angered his Western backers, particularly Belgium, when his soldiers attacked a student hostel in 1990, killing dozens of students.
Belgium cut aid in response. Mass opposition to Mr Mobutu grew through 1991.
Surrounded by his Israeli-trained presidential guard, he retreated to his opulent northern palace in Gbadolite, dubbed "Versailles in the Jungle", hurling defiance at his opponents. But the soldiers, angry at not receiving a pay rise, ran amok in Kinshasa in late 1991. France and Belgium sent in troops to protect foreign nationals. Looters killed at least 250 people.
Mr Mobutu's sacking in December 1992 of the reformist Prime Minister Etienne Tshisekedi, a one-time ally turned enemy, and the intimidation of the pro-democracy interim parliament by his presidential guard, brought further rebukes from abroad. France barred him from visiting his villa in the Riviera, while other countries denied him and his entourage visas.
Shrewd political manoeuvring enabled Mr Mobutu to neutralise a groundswell of public sympathy for Mr Tshisekedi. An impeachment threat by a transitional parliament came to nothing. Mr Mobutu, a pragmatist, began a process of rehabilitation with key donors - France, Belgium and the United States.
The 1994 exodus from Rwanda of over a million Hutus, fearing reprisals for the genocide of minority Tutsis there, worked in his favour. His co- operation helped to ease a humanitarian nightmare, bringing about a partial thaw in ties with the West. France softened its stance after he co-operated with a French military expedition to halt the Rwanda killings. In April 1996, Paris announced a resumption of aid after a five-year freeze.
In August 1996, Mobutu had prostate cancer surgery in Switzerland. In October, rebels took up arms in the east. As the Tutsi-led revolt spread, the rebels seized towns and territory and now control more than three- quarters of Zaire. Mr Mobutu, who spent much of the war convalescing in Europe, returned home on 22 March, in what many Zaire watchers saw as an attempt to negotiate a dignified withdrawal.Reuse content