"The election four years ago wasn't about me, it was about you," said Obama — his wife, two daughters and millions of Americans looking on — as he officially accepted his party's nomination at the Democratic National Convention.
"My fellow citizens, you were the change .... If you turn away now, if you buy into the cynicism that the change we fought for isn't possible, well, change will not happen."
Obama acknowledged the path he's trying to forge for Americans won't be quick or easy, and his remarks at the beginning of his address largely lacked the heady rhetorical flourishes he's known for.
He's not the same person he was four years ago, the 51-year-old Obama said in his primetime speech. Indeed, he's leaner, greyer and appears far more fatigued than when he bounded onto the stage in Denver four years ago to revel in his presidential nomination.
"You didn't elect me to tell you what you wanted to hear," Obama said. "You elected me to tell you the truth. And the truth is, it will take more than a few years for us to solve challenges that have built up over decades."
Nonetheless, there is light at the end of the tunnel, Obama said as he set the stage for the home stretch of a blistering U.S. election campaign.
"Know this, America: Our problems can be solved. Our challenges can be met. The path we offer may be harder, but it leads to a better place. And I'm asking you to choose that future."
Obama at times sounded defiant as he frequently rebuked his Republican rival for the White House, the wealthy Mitt Romney, and forcefully defended his four years in office against attacks from his foes.
"I refuse to ask families to give up deductions for owning a home, raising their kids just to pay for another millionaire's tax cut," he said.
He ridiculed the Republican mantra that bigger tax cuts and fewer regulations are the only way to kickstart the sputtering U.S. economic recovery.
"Over and over, we have been told ... that since government can't do everything, it should do almost nothing," Obama said.
"If you can't afford health insurance, hope that you don't get sick. If a company releases toxic pollution into the air your children breathe, well, that's just the price of progress. If you can't afford to start a business or go to college, take my opponent's advice and borrow money from your parents."
That's a vision for America that would take the country backwards, he added.
The president also mocked Romney for some of his foreign policy missteps.
"You don't call Russia our No. 1 enemy — and not al Qaida — unless you're still stuck in a Cold War time warp," he said to laughter from the crowd.
"You might not be ready for diplomacy with Beijing if you can't visit the Olympics without insulting our closest ally. My opponent said it was 'tragic' to end the war in Iraq, and he won't tell us how he'll end the war in Afghanistan. I have, and I will."
By the end of the address, Obama finally spurred a prolonged, jubilant ovation from the crowd as he beseeched Americans to stay the course and give him more time to pull the country out of its economic morass.
"If you give up on the idea that your voice can make a difference, then other voices will fill the void," he said, his voice rising.
"Lobbyists and special interests; the people with the $10 million checks who are trying to buy this election and those who are making it harder for you to vote; Washington politicians who want to decide who you can marry, or control health care choices that women should make for themselves."
Obama's first term has been bogged down by a devastating economic recession and a Republican vow to deny him four more years in office by attempting to obstruct his legislative agenda at every turn.
Some of the heaviest hitters of the Democratic party have been on hand all week at the cavernous downtown Time Warner arena to deliver the same message to Americans: vote for Obama on Nov. 6 to enable him to continue turning the country's fortunes around.
On Thursday, Vice President Joe Biden spoke of his perspective from a "ringside seat" in the Oval Office.
"Osama bin Laden is dead and General Motors is alive," Biden exclaimed to cheering Democratic delegates.
Biden, with his working-class background, has become a treasured adviser to the president over the past four years, even though he occasionally frustrates Obama with his off-the-cuff remarks and verbal missteps.
Obama's No. 2 told the crowd about the president's steely resolve to ensure the U.S. survived the economic meltdown that kicked in just as he took office in 2008.
"Day after day, night after night, I sat beside him, as he made one gutsy decision after another to stop the slide and reverse it," Biden said.
"I watched him stand up to intense pressure and stare down choices of enormous consequence. Most of all, I saw what drove him: His profound concern for the American people."
Sen. John Kerry, meantime, also ridiculed Romney's foreign policy gravitas.
"Ask Osama bin Laden if he is better off now than he was four years ago," Kerry, rumoured to be Obama's next secretary of state, told cheering delegates as he outlined Obama's foreign policy triumphs, in particular the death of the terrorist mastermind.
Romney and his running mate Paul Ryan, Kerry added, are the "most inexperienced twosome" ever to vie for the Oval Office. The Massachusetts lawmaker also mocked Romney's ill-fated summer trip abroad as a "blooper reel."
Obama's task ahead of the November election is to woo the substantial — and influential — bloc of independent voters in key swing states who will determine the outcome of the vote. He's particularly aiming to pull in white, male, working-class voters who currently far favour Romney.
Joey Beam, a 25-year-old chef in Charlotte, is one of those voters — a working-class white male in a key swing state who’s still weighing his vote but is leaning Democrat.
"Between Romney and Obama — I don't know, I think Obama has done the best he can do, and I'm not sure Romney is going to take care of the middle class," Beam said Thursday, enjoying a Pabst Blue Ribbon at a pub in downtown Charlotte hours before Obama was set to take the stage.
"I want there to be a stronger middle class so we can rebuild America and so that everybody has a chance for success. It can’t just be about the upper class."
The Obama campaign team has hit Romney hard on that front, portraying him as a wealthy, out-of-touch politician who wants to give tax breaks to the well-heeled at the expense of the middle class.