Barack Hussein Obama grew up on the beaches of Hawaii and the streets of Indonesia. He was raised by his white mother and barely knew his African father. He experimented with drugs and seemed headed nowhere, yet ended up excelling at elite universities.
His life, in short, has been far different from that of the average American voter.
But Obama had the political skills and charisma to turn those differences into an advantage in his US Senate race, which saw him handily defeating Republican Alan Keyes on Tuesday to become only the fifth black senator in US history.
He portrayed himself as a one-man American melting pot, straddling racial and cultural boundaries.
"We stand here as one people, as one nation proclaiming ourselves to be one America with the capacity to work together to create a better future for each other," Obama said in his victory speech.
Obama's father was a Kenyan student, also named Barack, who studied for several years in the US. His mother was a white Kansan who moved to Hawaii, where the couple met. The marriage didn't last long: They divorced while Obama was an infant, and he saw his father only once after that.
Obama, 43, lived in Indonesia for four years as a boy when his mother married again. His time there included schooling in the Bible and the Koran, sampling local dishes such as dog and snake, and wandering with other children, often encountering stark poverty and illness.
Today, he says that helped him understand the struggles facing so many around the world -- "the literal desperation of making sure you have enough to eat."
When he was about 10, Obama returned to his grandparents in Hawaii to attend a private school. Eventually, his mother divorced and left Indonesia to rejoin her son.
During his teenage years, Obama seemed headed straight for trouble.
His 1995 memoir, Dreams From My Father: A Story of Race and Inheritance, describes a period when he focused more on basketball than school. He drank, smoked pot, even experimented with cocaine.
"Junkie. Pothead. That's where I'd been headed," he wrote.
But Obama cleaned up his act, thanks to some concerned adults and the passage of time. "I think I just grew up," he said.
After his father died in a car accident, "Barry" Obama began using Barack. He became a community organizer, working with Chicago churches to help laid-off workers and remove asbestos from public housing.
"He just went from church to church, beating the pavement, trying to get every pastor in the community," recalled the Reverend Alvin Love of Lilydale First Baptist Church. "This skinny, scrawny guy trying to find out how we can make the community better."
Obama then decided to go to Harvard Law School, where he was elected the first black president of the Harvard Law Review. The position traditionally opens the door to clerking at the US Supreme Court and then a lucrative job, but Obama went to work for a small Chicago firm specializing in civil rights.
His first political campaign produced hard feelings.
He was recruited to replace a state senator who was running for Congress. But when the incumbent lost her congressional race, she decided to run for her old legislative seat and wanted Obama to step aside. Obama refused, and the well-regarded incumbent bowed out.
Four years later, he challenged US Representative Bobby Rush, but lost badly in the Democratic primary.