All sports are important particularly because teams build character and without character sports would not be fun.
The most successful athlete in Jamaica is Usaine Bolt because he broke the world record for 100 meter sprint.
Annika Sorenstam is arguably the greatest female golfer in history and the most successful Swedish female athlete ever.
This answer may vary depending on what you define as "successful," but generally, Michael Jordan is usually considered the most famous American athlete of his time.
Mary Lou Retton
Swedens shooter Jonas Jacobsson (16 golds)
The most successful and decorated Olympic athlete as of 2014 is Michael Phelps. He has 22 Olympic medals with 18 being gold medals.
Henry Carr
Phillip Adams is Australia's most successful Commonwealth Games athlete with eighteen medals (seven gold, nine silver and two bronze) from five Games (1982, 1986, 1990, 1994 and 2002).
He is a successful athlete with five NBA championship rings, a beautiful wife, and millions of dollars most people will never have in their life.
Tiger Woods is the most popular athlete in 2008.
If your an athlete you can do many sports but it is most associated with running.
Well, the athlete that won the most medals in Olympic history is Larissa Latynina of the USSR who won 18 medals (9 gold, 5 silver, 4 bronze) in Olympic competition.