Although Clinton had dismissed Obama in 2008 as undeserving of the presidency his wife Hillary Rodham Clinton was then seeking, on Sunday evening Clinton warmly declared "Barack Obama deserves to be re-elected president of the United States."
Obama is "beating the clock" to restore the nation's economy to health, Clinton told about 500 cheering supporters who had paid as little at $1,000 and as much as $20,000 apiece to see, as Obama put it, "two presidents for one."
Digging out of similar financial holes has historically taken five to 10 years, Clinton said.
Longtime Clinton backer and strategist Terry McAuliffe hosted the event, the first of three planned joint appearances for Clinton and Obama.
Once a tense rivalry, the relationship between Obama and Bill and Hillary Clinton has evolved into a genuine political and policy partnership. Suspicions remain in both camps, but both sides have a strong incentive for making the alliance workable and lucrative.
For Obama, Bill Clinton is a fundraising juggernaut, a powerful reminder to voters that a Democrat ran the White House the last time the economy was thriving. For the spotlight-loving former president, stronger ties with the White House and campaign headquarters mean he gets a hand in shaping the future of the party he led for nearly a decade.
Obama's re-election campaign has put Bill Clinton on notice that he will be used as a top surrogate, further evidence of how far the two camps have come since the bitter days of the 2008 Democratic primary battle between Obama and Hillary Clinton, now his secretary of state.
Neither Clinton nor Obama mentioned presumed Republican presidential nominee Mitt Romney by name, but both Democrats zinged Romney for his economic plan and foreign policy credentials.
Obama's likely GOP opponent "basically wants to do what they did before, on steroids," Clinton said, "which will get you the same consequences you got before, on steroids."
Obama said he and Hillary Clinton have "spent the past three-and-a-half years cleaning up after other folks' messes."
He ridiculed "the presumptive nominee on the other side" for "suddenly saying our No. 1 enemy isn't al-Qaida, it's Russia."
"I didn't make that up," Obama said to loud laughter. "I suddenly thought maybe I didn't check the calendar, and we're back in 1975."
Obama stood smiling, arms crossed, as Bill Clinton spoke. They complimented one another's performance in office, but with few personal asides or anecdotes that would suggest they are close or speak often.
Clinton guffawed when Obama made gentle fun of him, and himself, by noting that every presidential candidate always says the next election is crucial.
Obama acknowledged that he was about to make the same argument. "Well, let me tell you," he said to laughter and applause, "this one matters."
There was no direct reference to the bitter contest between Obama and Hillary Clinton in 2008, which split the Democratic Party. Obama's circle still remembers that the former president slammed the narrative set out by Obama's campaign as a "fairy tale." The tight network of Clinton family supporters recall that Obama sarcastically told Hillary Clinton that she was "likable enough."
The thaw started as a matter of political necessity: Their party was desperate to retake the White House after eight years of Republican rule. Hillary Clinton offered Obama a gracious endorsement, both Clintons campaigned for Obama, and the newly elected president picked his former rival to be America's chief diplomat.
It took longer for Obama's relationship with Bill Clinton to soften as the two men found common ground in the pressures of the presidency.
Clinton's willingness to be a good soldier for the Obama campaign could end up paying political dividends for his wife, who is frequently talked about in party circles as a potential presidential candidate in 2016 despite her repeated denials. Hillary Clinton has benefited enormously from her partnership with Obama, with her popularity skyrocketing during her time in his Cabinet.
Democrats say the overt signs of unity between the Clintons and Obama put the president at a distinct advantage over Romney. The former Massachusetts governor must soothe the wounds from his GOP primary fight and figure out whether the last Republican president, George W. Bush, will have a role in the 2012 race.
"It makes absolutely clear that, to the extent that there were different wings of the Democratic Party, there is now one wing of the Democratic Party," said Chris Lehane, a Clinton backer. "And it's the president's party."