Obama will be sworn in as the 44th U.S. president on January 20, 2009 and will face a crush of immediate challenges, from tackling an economic crisis to ending the war in Iraq and trying to overhaul the U.S. health care system.
McCain’s hopes for a surprise victory evaporated with losses in a string of key battleground states led by the big prizes of Ohio and Florida, the states that sent Democrats to defeat in the last two elections.
The win by Obama, son of a black father from Kenya and white mother from Kansas, marked a milestone in U.S. history. It came 45 years after the height of the civil rights movement led by Martin Luther King.
"It’s been a long time coming, but tonight, because of what we did on this day, at this defining moment, change has come to America," Obama, 47, told 125,000 ecstatic supporters gathered in Chicago’s Grant Park to celebrate.
"The road ahead will be long. Our climb will be steep. We may not get there in one year or even one term, but America — I have never been more hopeful than I am tonight that we will get there," he said.
Obama won at least 338 Electoral College votes, far more than the 270 needed. With results in from more than two-thirds of U.S. precincts, he led McCain by 51 percent to 48 percent in the popular vote.
Obama promised to ease the country’s sharp political divisions and work for those voters who did not support him.
A first-term Illinois senator, Obama led sweeping Democratic victories that expanded the party’s majorities in both chambers of Congress and marked an emphatic rejection of President George W. Bush’s eight years of leadership.
McCain, a 72-year-old Arizona senator and former Vietnam War prisoner, called Obama to congratulate him and praised his rival’s inspirational and precedent-shattering campaign.
"We have come to the end of a long journey," McCain told supporters. "I urge all Americans who supported me to join me in not just congratulating him but offering our next president our goodwill."
News of Obama’s win set off celebrations by supporters around the country, from New York and Chicago to Ebenezer Baptist Church in Atlanta, King’s home church.
"This is a great night. This is an unbelievable night," said U.S. Rep. John Lewis of Georgia, who was brutally beaten by police in Selma, Alabama, during a voting rights march in the 1960s.
The Rev. Jesse Jackson, a civil rights leader, joined the celebrations in Chicago, tears streaming down his cheeks.
Obama has promised to restore U.S. leadership in the world by working closely with foreign allies, to withdraw U.S. troops from Iraq in the first 16 months of his term and to bolster U.S. troop levels in Afghanistan.
But his immediate task will be tackling the U.S. financial crisis, the worst since the Great Depression. Obama has proposed another stimulus package that could cost about $175 billion and include funding for infrastructure and another round of rebate checks.
Obama took command of the race in the last month as the financial crisis deepened and as his steady performance in three debates with McCain appeared to ease lingering doubts among voters.
His judgment on handling the economic crisis appeared to help tip the race in his favor. Exit polls showed six of every 10 voters listed the economy as the top issue.
In addition to Ohio and Florida, Obama won Virginia, Iowa, New Mexico, Nevada and Colorado — all states won by Bush in 2004. McCain’s loss in Pennsylvania eliminated his best hope of capturing a Democratic-leaning state.
The vote capped an epic campaign marked by a rapid rise from obscurity for Obama and a bitter Democratic primary battle with New York Sen. Hillary Clinton, as well as McCain’s comeback from the political scrap heap to win the Republican nomination.
In the general election battle, Obama accused McCain of representing a third term for Bush’s policies and being out of touch on the economy. McCain’s campaign attacked Obama as a tax-raising liberal and accused him of being a "pal" with terrorists.
In a difficult political environment for Republicans, McCain struggled to separate himself from Bush. Exit polls showed three out of every four voters thought the United States was on the wrong track.
In the fight for Congress, Democrats were making big gains but appeared to be falling short of picking up the nine Senate seats to reach a 60-seat majority that would give them the muscle to defeat Republican procedural hurdles.
Democrats gained at least five Senate seats and knocked off two-high profile Republican incumbents — North Carolina Sen. Elizabeth Dole, a former presidential candidate and wife of 1996 Republican presidential nominee Bob Dole, and New Hampshire Sen. John Sununu.
Democrats also gained about 25 more House of Representatives seats to give them a commanding majority in that chamber.