Lending his signature dazzle to Obama's re-election campaign, the two-term former president told the Democratic convention that he believed "with all my heart" that the 44th president had led a remarkable, if incomplete, recovery.
Addressing a split electorate less than nine weeks ahead of November's election, Clinton said Obama had saved the economy from collapse and laid the foundation for the kind of growth seen during his own presidency in the 1990s.
"No president -- not me or any of my predecessors -- no one could have fully repaired all the damage he found in just four years," Clinton said.
"He has laid the foundations for a new, modern successful economy of shared prosperity, and if you will renew the president's contract, you will feel it. You will feel it."
"Folks, whether the American people believe what I said or not may be the whole election, I just want you to know that I believe it," Clinton said, his voice faltering slightly. "With all my heart I believe it."
After holding 15,000 of the Democratic faithful in Charlotte, North Carolina enthralled for over 45 minutes, Clinton was joined on stage by a smiling and energized Obama, leading to frenzied applause.
The Democratic standard bearers -- estranged during Obama's long 2008 primary battle with Hillary Clinton -- then embraced on stage, symbolizing a renewed determination to defeat their Republican rivals in November.
Obama will address the convention on Thursday at the same venue.
The campaign canceled plans for the president to give his nomination speech in a vast outdoor American football stadium, in which they had hoped to recreate the celebratory atmosphere of his 2008 convention address.
Officials said they could not risk thunder and lightning disrupting the event, Obama's best unfiltered chance to take his case to voters before the November 6 election, and moved the big set piece inside.
Setting the context for that address, Clinton, who was president between 1993 and 2001, offered a point-by-point rebuttal of the policies of Obama's rival, former Massachusetts governor Mitt Romney.
"The most important question is, what kind of country do you want to live in?" he asked.
"If you want a you're-on-your-own, winner-take-all society, you should support the Republican ticket," he said, referring to Romney's vows to cut spending, ease regulations and reduce the size of government.
Clinton also tried to give some empirical weight to the great ideological rift over economic policy that has come to define this election cycle.
"Since 1961, for 52 years now, the Republicans have held the White House 28 years, the Democrats, 24. In those 52 years, our private economy has produced 66 million private sector jobs.
"So what's the job score? Republicans, 24 million; Democrats, 42," he said to cheers.
Clinton is as popular now as when he was inaugurated in 1993, with a 66 percent approval rating, according to a recent CNN poll.
Even Romney campaign spokesman Ryan Williams praised the former president, saying that unlike Obama he had "worked with Republicans, balanced the budget, and after four years he could say you were better off."
"President Clinton's speech brought the disappointment and failure of President Obama's time in office clearly into focus," he said in a statement.
National polls put the rivals neck-and-neck, but Romney lags in key swing states and seems not to have received the bounce he was hoping for from last week's Republican convention.
Early in his speech, Clinton formally nominated Obama as the Democratic Party's presidential candidate.
"I want to nominate a man who's cool on the outside -- but who burns for America on the inside."
"I want a man who believes with no doubt that we can build a new American Dream economy," Clinton said.
"After last night, I want a man who had the good sense to marry Michelle Obama," Clinton quipped, drawing cheers and smiles from the First Lady the night after her own rousing convention speech.
In a roll call Democrats from all 50 states one-by-one announced their support for Obama, officially handing him the party nomination.