Barack Obama made history when he was elected the United States' first African-American president in November 2008, and he swept to re-election with a victory over Republican Mitt Romney in 2012.
In a speech to supporters in Chicago after winning the election, Obama pledged to work with Democratic and Republican leaders to reduce the nation's federal deficit, fix the tax code, reform immigration and reduce the nation's dependence on foreign oil.
Obama's first term in office had been dominated by the passage of his Patient Protection and Affordable Care Act, colloquially known as "Obamacare", which he signed into law despite fierce Republican opposition.
Obama also ordered the bailout of the country's struggling car industry in 2009 and signed into law a repeal of the military's controversial "don't ask, don't tell" policy preventing gay people from serving.
He also signed into law the Dodd-Frank Wall Street Reform and Consumer Protection Act, which tightened regulation of the financial system.
On the international stage, Obama has withdrawn US troops from Iraq, a conflict he opposed from the beginning, although thousands of US troops remain in Afghanistan.
The president has failed to close the detention centre at Guantanamo Bay, as he had promised in 2008.
In 2011, the president ordered a team of Navy SEALs to kill Osama bin Laden, the leader of al-Qaeda, at his compound in Pakistan.
The son of a Kenyan father and US mother, Obama was born in Hawaii in 1961.
|Obama's 2008 candidacy captured the US
public's imagination [Reuters]
After his parents' divorce, his mother remarried and he lived in Indonesia for several years.
Obama later obtained his degree in New York and spent several years working for church groups assisting the poor in Chicago in the midwestern state of Illinois.
Eventually, like several other presidential candidates, he entered the legal profession, becoming the first African-American president of the prestigious Harvard Law Review while obtaining his law degree.
He then returned to Chicago, teaching and working as a civil rights lawyer before entering the Illinois state senate in 1997.
Path to power
In 2004, Obama was elected to the US senate, only the third African-American to achieve such a post since the US' Reconstruction era of the late 19th century.
Not long afterwards, Obama delivered the keynote speech at the Democratic Party's annual convention in Boston, Massachusetts, in which he criticised George Bush, the US president at the time, and called for an end to the Iraq war.
The speech sparked national interest in the young senator, and soon led to a wave of queries from the media over whether he would announce his candidacy for the Democratic presidential nomination.
When he finally did so, there was a media frenzy. The young, photogenic senator was feted by many as the new face of the Democrats.
But he only secured the nomination after a long and at times bitter presidential primary campaign against rival Hillary Clinton, the New York senator and former first lady.
After he won the presidency, she accepted his offer to become secretary of state.
Four years on
The 44th US president took office with an approval rating of more than 80 per cent. As his first term draws to a close, however, his approval ratings have hovered slightly below 50 per cent.
Although the unemployment rate fell below eight per cent in September, for the first time since Obama took office, it is still high by historical standards.
National polls show the president running roughly even with his Republican opponent, former Massachusetts Governor Mitt Romney, although Obama has small leads in some critical swing states such as Ohio.
Some speculate that Obama's response to Hurricane Sandy, a 'super storm' that hit the East Coast a week before election day, may have given him a boost in the polls.
One exit poll found two-thirds of voters cited Obama's response to the storm as a factor in their vote.