"Together, we will change this country and change the world." This was Barack Obama's rallying cry to Americans in the closing days of a campaign which saw him become the first black President of the United States.
A politician from whom the world expects great things, Mr Obama described the 2008 election as a "defining moment" for Americans who were looking for "real and lasting change that makes a difference in their lives".
His unifying message of hope and change for America, and of a different kind of politics in Washington, saw unprecedented levels of interest in the election and energised millions of people, young and old, black and white, Republicans and Democrats, to vote and have a say in their future.
Repeatedly breaking fundraising records and drawing tens, if not hundreds, of thousands of supporters at rallies, he simultaneously showed he was tough enough to beat the Clinton political machine and Republican attack adverts while keeping his cool on the trail.
As he became the first presidential candidate in 16 years to air a 30-minute primetime infomercial on several US TV networks, he declared: "I will not be a perfect President. But I can promise you this - I will always tell you what I think and where I stand."
The advert, which cost about £2 million, emphasised his financial dominance over rival John McCain and was seen in more than 20% of homes across the country.
"America, the time for change has come," he said to loud cheers as the commercial cut to him on stage as a live campaign rally.
"We can come together as one nation, and one people, and once again choose our better history."
The 47-year-old Illinois senator's message of hope and change comes at a time when many Americans are unhappy with an unpopular war in Iraq, disillusioned with the nation's position in the world, and suffering at home from a global financial crisis caused by greed on Wall Street.
His high rhetoric and record-breaking rallies, including an audience of 200,000 people in Berlin, have seen him portrayed as a Messiah-like figure.
And he took his national convention to an outdoor stadium, standing in front of a stage resembling a Greek temple, or a federal building in Washington, as he accepted his party's nomination on the 45th anniversary of Martin Luther King Jr's "I Have a Dream" speech.
"America, we are better than these last eight years, we are a better country than this," he said, as he compared Mr McCain to the unpopular President George Bush.
His former rival Hillary Clinton said he was her candidate in what was arguably the most important speech of her life and her husband, former President Bill Clinton, declared Mr Obama was "the man" to lead America, despite clashing with him during the primary elections.
On his way to the White House, Mr Obama also confronted the key issue of race in US society in a bold speech in March.
He said America could not afford to ignore the race issue and added that incendiary comments by his former pastor the Rev Jeremiah Wright reflected the "complexities of race in this country that we've never really worked through - a part of our union that we have yet to perfect".
It was an attempt to diffuse the potentially damaging row over Mr Wright, whose inflammatory comments included describing the September 11 terror attacks as America's "chickens coming home to roost", and was widely seen as a success.
With only two years' experience in national office, Mr Obama announced his White House bid from the steps of the Old State Capitol building in Springfield, Illinois, in February last year, symbolically linking his campaign to former president Abraham Lincoln's 1858 House Divided speech.
He energised the youth vote during the primary season, huge crowds have greeted him at rallies at home and abroad, his two books have both become best-sellers, and many believe an Obama White House in 2009 might help heal the nation's scarred racial past.
But several conservative talk show hosts frequently referred to his middle name, Hussein, and the senator, a Christian, has faced repeated suggestions that he is Muslim.
At a charity fundraiser in New York last month he joked that he had "got my middle name from somebody who obviously didn't think I'd ever run for president".
Born in Honolulu, Hawaii, in August 1961, Barack Hussein Obama Jr was named after his Kenyan father, whose first name means "blessed" in Swahili.
His father grew up in Kenya herding goats but gained a scholarship to study in Hawaii where he met Mr Obama's mother, Ann Dunham, of Kansas.
While still a toddler, his father went to study at Harvard but there was no money for the family to go with him and he later returned to Kenya alone before his parents divorced.
Mr Obama's mother married Indonesian Lolo Soetoro and the young child spent four of his pre-teen years in that country's capital, Jakarta.
He then moved back to Hawaii to live with his grandparents and attend school, before studying political science at Columbia University in New York.
He moved to Chicago where he spent three years as a community organiser, before attending Harvard Law School in 1988, where he became the first African-American president of the Harvard Law Review.
Mr Obama later returned to Chicago to practise civil rights law, representing victims of housing and employment discrimination.
He married lawyer Michelle in 1992 and they have two young daughters, Malia Ann, 10, and Sasha, seven.
And it has been a meteoric rise for the man who first attracted international attention just four years ago when he made a keynote speech at the 2004 Democratic National Convention, calling for more financial support for families of US troops killed in action and urging unity.
He became the only current African American US senator the following year - and only its fifth in history.
Labelling his own campaign for change in all aspects of life - from foreign policy to healthcare, education and the legislative process - as an "improbable quest", Mr Obama still insists "few obstacles can withstand the power of millions of voices calling for change".
Defining his presidency, Mr Obama said it was time to "reclaim our American dream" and told voters: "At this defining moment in history, you, each and everyone of you, can give this country the change that we need."