Michael Phelps - 22
2004-12 (18 Gold, 2 Silver, 2 Bronze) Arguably the biggest story line coming into this Olympics was Michael Phelps' pursuit of becoming the most medaled Olympian in history. After his gold medal-winning performance with the U.S. in the 4x200 relay team, his mission was accomplished in his third Olympics. Phelps then continued his medal run by beating teammate Ryan Lochte for gold in their final showdown in the 200-meter individual medley. In the final individual race of his career, he won the 100-meter butterfly. Not only does Phelps have the most medals, but also 18 of them are gold -- twice as many as the next best gold haul.