Don King gained fame in 1974 by sponsoring the boxing match between Muhammad Ali and George Foreman in Zaire, popularly known as "The Rumble in the Jungle." He consolidated his position as an influential promoter the next year by sponsoring a third match for Ali against Joe Frazier in Manila, the capital of the Philippines, which King named the "Thrilla In Manila."

Apart from Ali, Frazier and Foreman, he has promoted such boxers as Evander Holyfield, Félix Trinidad, Mike Tyson, Larry Holmes, Carlos De Leon, Wilfredo Benitez, Wilfredo Gomez, Roberto Duran, Julio Cesar Chavez, Juan Laporte, Edwin Rosario, Salvador Sanchez, John Ruiz, Hector Camacho, Christy Martin, Aaron Pryor, Alexis Arguello, Oscar de la Hoya, and many others.

In May 2003, King was sued by Lennox Lewis, who wants 385 million dollars from the promoter, claiming King used threats to pull Tyson away from a rematch with Lewis. This is one of several lawsuits King has gone through.

Don King is well-known for his eccentric behavior and outlandish style. His catchphrase is "Only in America!" He has a rather unusual hairstyle, and is fond of wearing loud, brightly colored clothing and lots of jewelry. He is also a very grandiose public speaker.

In 2004, Don King became increasingly active in the re-election campaign of George W. Bush. Although a Democrat, King actively supported George W. Bush's re-election.