Obama, along with popular wife Michelle will throw down the gauntlet to Republican presumptive nominee Mitt Romney with two full-scale political events in the crucial battleground states of Ohio and Virginia.
"Welcome to the general election," Obama's campaign manager Jim Messina told reporters late Wednesday, launching a new, intense six-month sprint up to the day when Obama will ask voters for a second term on November 6.
The announcement came a day after Romney finally locked in his party nomination ahead of a general election campaign certain to focus on the uncertain US economic recovery after the worst recession since the 1930s.
The back-to-back rallies in Columbus, Ohio and Richmond, Virginia, will see Obama try to fire up the coalition of young, educated middle class, Hispanic and African American voters which swept him to power in 2008.
But four years on, with the euphoria dissolved in the slog of governing in an age of crisis, Obama is expecting Romney will put a much stronger fight than the 2008 Republican nominee John McCain.
"For the better part of last year, Mitt Romney has been trying to tear down President Obama with a dishonest campaign that even his republicans have criticized," said Messina.
"Well, the monologue is over. Now Romney has to put his record and his agenda up against the President's."
Though the May 5 rallies will be the first official campaign events, Obama has been piling up cash at numerous fundraisers for months as he builds what aides said is the most comprehensive grass roots campaign in US history.
Republicans have accused him of blurring the line between his official duties and reelection activity for instance as he spoke to students during a swing through North Carolina, Colorado and Iowa over the last two days.
Obama has also been drawing sharp implicit contrasts between himself and Romney, though rarely mentions the former Massachusetts governor by name, especially on issues like raising taxes on the richest Americans.
The Obama campaign portrays the president as a warrior for the middle classes who will fight for an economy where everyone -- not just the wealthy -- get a "fair shot."
They also claim that Romney would return America to "back to the future" policies of tax cuts for the rich and lax regulation that caused the economic crisis in the first place.
Obama aides also Wednesday took aim at Romney's claim that his career in business, which earned him a huge personal fortune, qualifies him to clean up what he sees as the president's failed economic policy.
Romney will focus on 8.2 percent unemployment and argue that though Obama did not cause the recession, he has made it unnecessarily long.
But senior Obama strategist David Axelrod ridiculed the idea that Romney's career as a venture capitalist gave him special economic expertise.
"His business career was not about job creation, it was about wealth creation for himself and his partners," Axelrod said.
"Often it came through vehicles like outsourcing, leveraging companies with debt, bankrupting companies and making money off those bankruptcies."
"There's nothing in his record to suggest that he's the champion of an economy that works for the middle class."
But Romney spokeswoman Andrea Saul accused the Obama campaign of deflecting from the real issue of the election with negative tactics.
"Americans shouldn't be surprised that President Obama's campaign will attack Mitt Romney for his experience in creating jobs.
"Unfortunately, voters will have to expect that the Obama campaign will be running a campaign based on personal attacks to divert, distract and distort. Like Mitt Romney said last night, 'It's still the economy, and we're not stupid.'"