Barack Obama is the 44th President of the United States and the first African-American to hold the office. He is a Democrat. In our timeline, Obama won the 2008 United States presidential election against Republican John McCain. He was inaugurated on January 20, 2009.
Since Democratic President Garrett Walker wins the 2012 election shortly before the start of the first season, it is unclear whether Obama has been president within the show's universe, or how his presidency fits into the House of Cards timeline. He has not yet been referred to within the show itself, although, while resigning, Walker congratulated Frank for being the 46th president of the United States (Obama being the 44th, Walker would be 45th).