Obama stressed the importance of the moment to around 70,000 supporters during an outdoor rally in Chicago's Grant Park, telling them that "change has come."
"This is our moment. This is our time... to reclaim the American Dream and reaffirm that fundamental truth -- that out of many, we are one; that while we breathe, we hope, and where we are met with cynicism, and doubt, and those who tell us that we can't, we will respond with that timeless creed that sums up the spirit of a people: yes we can," Obama told the electrified crowd late Tuesday.
Obama rode widespread concerns about the unstable U.S. economy and dissatisfaction with the presidency of George W. Bush to victory, capturing battleground states such as Florida, Ohio, Indiana and Virginia.
But beyond the political shift from eight years of Republican power to the Democratic Party, Obama also acknowledged the historic nature of his election.
"If there is anyone out there who still doubts that America is a place where all things are possible; who still wonders if the dream of our founders is alive in our time; who still questions the power of our democracy, tonight is your answer," Obama said.
The massive Chicago crowd erupted at 11 p.m. ET when the media projected Obama had captured the Electoral Votes needed to win the presidency. The Illinois senator spoke less than an hour later.
"The crowd exploded when it was projection was that Obama would become the 44th president of the United States," NewsHour Senior Correspondent Judy Woodruff reported from Chicago. "There's a reverence that's taken effect among the thousands of people here... It's a moment of awe. People here know they're witnessing history... I don't think I've seen anything like this."
Within moments of the media projection for Obama, his Republican opponent, Arizona Sen. John McCain, took to the lawn outside a hotel in Phoenix, Ariz. to congratulate the president-elect and concede the race.
"We have come to the end of a long journey," McCain told a crowd outside the Biltmore Hotel. "The American people have spoken and spoken clearly."
"This is an historic election and I recognize the significance it has for African-Americans and the special pride that must be theirs tonight," McCain told supporters.
Analysts were quick to agree with the Republican's assessment.
"Americans will look at their country differently tomorrow," NewsHour analyst Mark Shields said Tuesday night.
And it was a diverse electorate that supplied the historic change.
"It was not just a single voting group that put Obama over the edge. Obama did four points better among white men than John Kerry, two points better among white women," the Hotline's Amy Walter said. "The economy is a real reason for this. Cut across all ethnic groups and groups in terms of their income levels."
And while economic issues played a critical role in the vote, many stressed the underlying racial component to Tuesday's vote.
"Now we see many whites choosing reason over race, hope over fear," the New York Times quoted Jesse Jackson as saying.
"Many whites voted for him because he was black," Jackson said of Obama. "They saw a redemptive moment. They could say 'we're better than we have been.'"
In a serious and reflective address, Obama turned from the heat of the campaign to face the serious challenges he will face in January as he becomes president. In the speech, Obama reached out to those who had voted for his opponent, seeking to build bridges left weakened by an at-times harsh campaign.
"As Lincoln said to a nation far more divided than ours, 'We are not enemies, but friends... though passion may have strained it must not break our bonds of affection,'" Obama said. "And to those Americans whose support I have yet to earn -- I may not have won your vote, but I hear your voices, I need your help, and I will be your president, too."
And as he sought to assuage any bitterness among those who voted against him, political experts were near universal in their praise of the Obama campaign's careful and meticulous run for the White House, a campaign that saw him oust the presumed Democratic front-runner Hillary Clinton, raise record sums of money from a record number of donors and reshape the modern political campaign.
"Beginning with the caucuses in the primaries, organizing these in states where Democrats had never competed. He began to build a foundation of voters who understood that their small donations mattered, that their voices were heard ... This was a grassroots campaign, that likes of which we have never seen and I bet that the next campaigns that you seen in the future campaigns will build on this foundation," Obama adviser and former journalist Linda Douglass told the NewsHour.
Although the campaign spread throughout the country and organized in traditionally Republican strongholds, they also focused many of their resources in states seen as critical.
In particular, Obama targeted Ohio, Virginia and other states that narrowly went to President Bush four years ago.
"One line that the Obama campaign likes to give is that no Ohio resident lives more than 38 miles from an Obama campaign office," NPR reporter David Greene, who was reporting from Columbus, Ohio, told the NewsHour. "That gives you a sense for really how much they blanketed the state."
It was also a campaign that faced critical moments where they exceeded the convention wisdom of pundits.
"Iowa -- that was Obama's crystallizing moment. When he won Iowa in a turnout that was unprecedented by Iowa standards ... it proved that an African-American candidate could win in an overwhelmingly white state. They realized 'this guy really has a chance.' Iowa became really the litmus test ... for the campaign," Mark Shields said.
But beyond the political skill of the Obama campaign, it was the historic nature of the Illinois senator's election that drew praise from his former opponent and analysts.
"In a larger sense, it would also be an extraordinary ... announcement to the rest of the world. Don't write us off. Don't pigeon-hole the United States," historian Richard Norton Smith said of an Obama win. "How many other Democratic societies around the world are capable of doing this themselves?"
"In 50 years when people write textbooks this will be the first page of a chapter," New York Times columnist David Brooks said after Obama's address. "A chapter ended and a chapter of some sort is beginning."