Andre Kirk Agassi  born 29 April 1970, in Las Vegas, Nevada) is an American retired professional tennis player and former World No. 1, who was one of the game's most dominant players from the early 1990s to the mid-2000s. Generally considered by critics and fellow players to be one of the greatest tennis players of all time, Agassi has been called the best service returner in the history of the game. Described by the BBC upon his retirement as "perhaps the biggest worldwide star in the sport's history", Agassi compiled performances that, along with his unorthodox apparel and attitude, saw him cited as one of the most charismatic players in the history of the game. As a result, he is credited for helping to revive the popularity of tennis during the 1990s.
In singles tennis, Agassi is an eight-time Grand Slam champion and a 1996 Olympic gold medalist, as well as finishing runner-up in seven other Grand Slam tournaments. His four Australian Open titles are an Open Era record (shared with Novak Djokovic and Roger Federer). He is one of four male singles players to achieve the Career Grand Slam (all four Grand Slam championships) in the Open Era and one of seven in history, the first of two to achieve the Career Golden Slam (Career Grand Slam and Olympic gold medal), and the only man to win the Career Golden Slam and the ATP Tour World Championships (won in 1990): a distinction dubbed as a "Career Super Slam" by Sports Illustrated.
Agassi was the first male player to win all four Grand Slams on three different surfaces (hard, clay and grass), and the last American male to win the French Open (1999) and the Australian Open (2003). He also won 17 ATP Masters Series titles and was part of a winning Davis Cup team in 1990 and 1992. Agassi was troubled by personal issues during the mid-to-late 1990s and sank to World No. 141 in 1997, prompting many to believe that his career was over. Agassi, however, returned to World No. 1 in 1999 and enjoyed the most successful run of his career over the next four years. During his 20-plus year tour career, Agassi was known by the nickname "The Punisher".
After suffering from sciatica caused by two bulging discs in his back, a spondylolisthesis (vertebral displacement) and a bone spur that interfered with the nerve, Agassi retired from professional tennis on 3 September 2006, after losing in the third round of the US Open. He is the founder of the Andre Agassi Charitable Foundation, which has raised over $60 million for at-risk children in Southern Nevada. In 2001, the Foundation opened the Andre Agassi College Preparatory Academy in Las Vegas, a K-12 public charter school for at-risk children. He has been married to fellow tennis star  since 2001.