Politically, the term was first applied to James K. Polk, a relatively unknown Tennessee Democrat who won the Democratic Party's 1844 presidential nomination over a host of better-known candidates. Polk won the nomination on the eighth ballot, and went on to win the 1844 presidential election.
Other famous dark horse candidates for the United States presidency include:
More recently, some have described Bill Clinton as a dark horse, after he overcame a crowded field of Democratic hopefuls to win the 1992 presidential election. The same has been said about Jimmy Carter and the 1976 presidential election.
The term dark horse is also used outside the political context. Surprising or unlikely nominations for such prizes as the Academy Award are referred to as dark horses. It is also used in sport, in connection with competitors or teams that, despite not being favourites, are expected to challenge to win.