Obama was declared the winner after several gut-wrenching hours that saw the president and his White House rival, Mitt Romney, spend election night much as they did their bruising, $2.6 billion campaign — in a tense nail-biter.
Supporters at Obama's Chicago headquarters greeted the president with euphoria as he strode to the podium to the upbeat strains of Stevie Wonder's "Signed, Sealed, Delivered," his 2008 campaign anthem.
"Tonight in this election, you, the American people, remind us that while our road has been hard, while our journeys have been long, we have picked ourselves up, we have fought our way back, and we know in our hearts that for the United States of America, the best is yet to come," Obama said.
At Romney headquarters in Boston, meanwhile, the mood was grim following an election long considered well within the Republican's grasp.
"This is a time of great challenges for America," a composed, gracious Romney told his supporters after it took him more than an hour to concede after the president clinched the election.
"I pray that the president will be successful in guiding our nation."
Obama's success this year was in contrast to his historic triumph in 2008, when he became the country's first African-American president and won the White House on an inspiring message of hope and change.
In 2012, Obama's rhetoric was decidedly less soaring — although his victory speech on election night certainly showed a return to form.
"We are an American family and we rise and fall together as one nation and as one people," he said.
But on the campaign trail, it was little wonder Obama chose to remind Americans he understood their impatience with him — the nation's citizens, after all, are still struggling to recover from a devastating economic recession that took unrelenting hold of the country soon after the president took office.
Obama, indeed, has become the first incumbent president since Franklin D. Roosevelt to win a second term with an unemployment rate above 7.4 per cent.
Unlike 2008, the president no longer pledges to dramatically change the toxic political culture in the U.S. capital — not surprising given the rigid opposition he's faced from Republicans in the House of Representatives since they took back control of the chamber in 2010.
Instead, he's vowed to finish the work he'd started and urged Americans to stand by him.
And even though Obama secured a second term, the election exposed bitter partisan and demographic fault lines in the United States that threaten to endure for years to come.
Obama handily won the votes of women, young Americans, African-Americans and Hispanics — in fact, the president got almost 70 per cent of the Latino vote, the fastest growing demographic in the United States.
In Pennsylvania, the high turnout of African-American voters — reportedly even higher than it was in 2008 — was thought to have played a critical role in the president's victory there.
Romney, meantime, won over older Americans, working-class whites and those with family incomes of $50,000 a year or more.
Obama's triumph was the long-awaited culmination of one of the hardest-fought presidential campaigns in recent U.S. history. Indeed, he only narrowly appeared to have won the popular vote over Romney.
But under the American system, presidential candidates compete not for popular vote, but for the electoral college votes up for grabs stateside. Those votes are assigned based on a state's population and representation in Congress.
Eight states, representing 89 electoral college votes, were considered battlegrounds: Colorado, Iowa, Wisconsin, Ohio, Virginia, Florida, North Carolina and New Hampshire. Romney won only North Carolina; Florida was too close to call.
Throughout the campaign, Romney insisted the president had failed miserably to deliver on his heady promises of 2008, assailing him in particular for his handling of America's persistent economic woes.
Romney, a wealthy one-time venture capitalist, asserted that his own business experience would make him a better choice for Americans.
But many left-leaning Americans deeply distrusted the Republican, particularly after the emergence of a secretly recorded videotape in early September that showed him disparaging almost half of the electorate as government freeloaders.
Hispanics, meantime, never forgave Romney for remarks he made during primary season, when he said illegal immigrants should "self-deport."
The 65-year-old former Massachusetts governor nonetheless fought until the bitter end, making last-minute campaign appearances Tuesday in Ohio and Pennsylvania even as millions of Americans were casting their ballots.
"This is a big day for big change," Romney said in Richmond Heights, Ohio, alongside his running mate, Paul Ryan.
"The country's been going in the wrong direction for the last few years; we're going to steer it back onto a course that's going to help the American people have a brighter future."
Obama, for his part, officially ended his final political campaign with an emotional appearance with his wife, Michelle, on Monday night in Iowa, where he won his first primary season contest in 2008.
The 51-year-old president spent election night in Chicago, playing basketball with longtime friends — former Chicago Bulls forward Scottie Pippen was on his team — before awaiting the results.
More than 45 million Americans had already cast their ballots in early voting by the time Tuesday rolled around.
For those who trudged to the polls on election day, sporadic problems awaited them at polling stations across the country, especially in the key battleground states.
The race for the White House had been a dead heat, with polls showing Obama and Romney tied nationally for weeks as they offered up competing visions for the country.
The president, however, had pulled ahead nationally in a pair of polls released this week. Obama also had persistent, narrow leads in several of the battleground states; he also reportedly had the edge in early voting.
Obama's improved showing in a slew of recent surveys suggested his response to mega-storm Sandy, which devastated New York and New Jersey last week, had won him crucial support in those swing states.
Most of those surveyed have given the president high marks when asked about his handling of federal relief efforts.
Sandy underscored one of the key themes of the election — the role of government in the lives of citizens. Romney once suggested federal funding for disaster relief was "immoral." The plight of the middle class was another primary topic of disagreement.
Obama has been vilified by Republicans for a tepid economic recovery following the financial meltdown that took stubborn hold of the United States just as he won the White House in 2008.
They've also accused him of being a socialist, saying he's expanding government and creating a welfare state while raising taxes and running up the national debt to monstrous levels.
In fact, Obama has cut taxes and shrunk government during his four years in office, slashing more than half a million federal jobs since 2009.
His predecessor, George W. Bush, ran up the debt to unprecedented levels while financing two overseas wars. The billions Obama has spent in corporate bailouts and economic stimulus measures are credited by many economists with putting the brakes on what might have been a full-fledged depression.
Democrats, meantime, warned Americans that Romney and Ryan would slash cherished entitlement programs, including Medicare, and push through 1950s-era social policies on abortion and contraception.
They also said Romney would roll back Obama's Wall Street regulations to the relatively lawless state of affairs that allowed the financial meltdown to happen in the first place.
Team Obama also mocked Romney's proposals to cut taxes across the board, increase defence spending and dramatically reduce the national debt as mathematically impossible, insisting the middle class would ultimately pay the price under a Republican presidency.
And yet Tuesday night's congressional winners and losers were every bit as important as the ultimate White House victor. Congress, after all, is more powerful than the executive branch in terms of bringing to life — or snuffing out — a president's legislative hopes and dreams.
The makeup of Congress remained relatively unchanged, with Republicans maintaining control of the House of Representatives and Democrats dominating the Senate.
That means Obama will face a Republican House that's no warmer to his agenda than it has been for the past two fractious years.Suggest a correction