The most successful Olympian in history is Michael Phelps, an American swimmer. He holds an astounding record of 23 Olympic gold medals and a total of 28 medals across four Summer Olympics (2004, 2008, 2012, and 2016). Phelps's dominance in the pool, particularly in the freestyle and butterfly events, has made him a legendary figure in athletics. His achievements have set benchmarks that inspire aspiring athletes worldwide and have significantly influenced the sport of swimming.