Obama, who calls Chicago home, parlayed his U.S. Senate seat into the presidency by defeating Republican candidate Sen. John McCain of Arizona.
While Obama wasn't able to fulfill his first-day promise to close the detention facility for accused terrorists at Guantanamo Bay, Cuba, he did make good on his pledge to get U.S. combat troops out of Iraq.
U.S. combat troops in Afghanistan are to be out by the end of 2014.
Obama also made good on his pledge to hunt down al-Qaida founder Osama bin Laden, who was killed in May 2011 during a U.S. Navy SEALs raid on the radical cleric's compound in Abbottabad, Pakistan.
The first bill he signed into law was the Lily Ledbetter Act, which states the 180-day statute of limitations for filing an equal-pay lawsuit concerning pay discrimination is reset with each new paycheck affected by the discriminatory action. Ledbetter's attempts to sue for pay discrimination was rebuffed by the U.S. Supreme Court, which ruled the suit should have been filed within 180 days of her receiving her first paycheck -- no matter she didn't know for years her pay did not approach that of her male colleagues.
A month after he took office, Congress passed Obama's $787 billion stimulus package to help jump start a moribund U.S. economy by creating jobs and spurring economic activity.
Obama's signature domestic legislation, the Affordable Care Act, reformed the U.S. healthcare system and passed while Democrats held majorities in the House and Senate.
In the wake of the meltdown in the financial sector, Obama pushed and got passed a Wall Street reform package that included the creation of a financial consumer protection agency.
Obama signed into law the repeal of the military's "don't ask, don't tell" policy, allowing openly gay and lesbian individuals serve in the armed forces.
After the 2010 midterm elections, in which Democrats lost control of the House and saw their supermajority in the Senate shrink, Obama worked around Congress by signing a series of executive orders affecting areas such as home loans, immigration, student loans and K-12 education.
Internationally, Obama sought to "reset" relations with Russia and worked with Russian President Dmitry Medvedev to expand diplomatic relations into technology, culture and education. A second strategic arms treaty that called for the mutual reduction of nuclear arms, among other things, was passed by lawmakers in both countries on Obama's watch.
Concerning Iran, the Obama administration implemented more economic sanctions and travel bans over the Islamic republic's nuclear work that the West believes directed toward the development of a nuclear warhead.
In 2009, the Norwegian Nobel Committee announced Obama won the Nobel Peace Prize "for his extraordinary efforts to strengthen international diplomacy and cooperation between peoples."
When he announced his intent to run for the presidency in February 2007, the first-term U.S. senator said he could not wait until politics "boil the hope out of him." His best-selling third book was called "The Audacity of Hope: Thoughts on Reclaiming the American Dream."
Obama said his late mother, Stanley Ann Dunham, who died of cancer at 53, and his grandmother, Madelyn Payne Dunham, 86, taught him how to dream and value hard work, and were the guiding forces of his life.
Obama described his birth at Kapi'olani Medical Center for Women and Children in Hawaii Aug. 4, 1961, to a young white woman from Kansas and a father of Luo ethnicity from Nyanza province in Kenya, as an "all-America" story transcending orthodox racial stereotypes and experience. Even his name -- Barack means "one who is blessed" in Swahili -- seemed to signal great things for Obama.
After a scholastic career that included being the first black president of the Harvard Law Review, Obama worked as a community organizer in Chicago. He won a seat in the Illinois Senate in 1996 and held it until he ran for the U.S. Senate in 2004.
It was that year he burst upon the national political scene with a stirring keynote speech at the Democratic National Convention. That fall he won his Senate seat with more than 70 percent of the vote.
Before launching his political career, Obama joined the Chicago law firm of Miner, Barnhill & Galland to practice civil rights law. He had met his future wife, Michelle Robinson, in 1989 when he was a summer intern at Sidley & Austin, a corporate law firm. They married in 1992 and have two daughters, Malia, 14, and Sasha, 11.