Became the youngest swimming world-record holder ever at age 15
In 2003, set five world records in one international meet
Claimed eight medals (six gold, two bronze) in his Olympic debut, the 2004 Games in Athens
Started the Swim with the Stars Tour (with Ian Crocker and Lenny Krayzelburg) after the 2004 Olympics to promote the sport
Won eight gold medals at the 2008 Olympics in Beijing, breaking fellow swimmer Mark Spitz's record for most first-place finishes in a single Games
In 2008, established the Michael Phelps Foundation, a nonprofit organization that promotes swimming and helps kids build healthy lives through the sport
Captured four gold and two silver medals at the 2012 Olympics in London, breaking the all-time record with 22 total Olympic medals
Retired following the 2012 Games, but returned to competition in May 2014
Is a two-time Associated Press Athlete of the Year (2008, 2012)
With his qualification for the 2015 Olympics in Rio, became the first American male swimmer to make five Olympics; chosen as the flag-bearer for the Opening Ceremonies
Won six golds at the 2016 Olympics in Rio and was part of a three-way tie for silver in the 100m butterfly, bringing his total medal count to 28, with 23 of them gold