Barack Obama's tenure as the 44th president of the United States began with his first inauguration on January 20, 2009, and ended on January 20, 2017. Obama, a Democrat from Illinois, took office following his victory over Republican nominee John McCain in the 2008 presidential election. Four years later, in the 2012 presidential election, he defeated Republican nominee Mitt Romney, to win re-election. Obama is the first African American president, the first multiracial president, the first non-white president, and the first president born in Hawaii. Obama was limited to two terms and was succeeded by Republican Donald Trump, who won the 2016 presidential election.

Barack Hussein Obama II is an American politician who served as the 44th president of the United States from 2009 to 2017. A member of the Democratic Party, he was the first African-American president in United States history. Obama previously served as a U.S. senator representing Illinois from 2005 to 2008, as an Illinois state senator from 1997 to 2004, and as a community service organizer, civil rights lawyer, and university lecturer.