Clijsters, known as Kim Kong, Killing Kim or Kim Possible to many fans, is recognized for her deep, powerful, well-placed groundstrokes, as well as her court-wide defense, characterized by speed and athleticism, including the use of splits in returning some shots

Clijsters is the daughter of a successful soccer player, Lei Clijsters, and a national gymnastics champion, Els Vandecaetsbeek. In reference to her playing style, Clijsters claim to have inherited her a footballer's legs from her father (e.g. when she runs down to retrieve every shot), and a gymnast's flexibility from her mother (e.g. when she makes the split, see trademark move). [2]

Kim Clijsters has a younger sister named Elke Clijsters, who was an accomplished junior player. She finished 2002 as the ITF World Junior Doubles champion, but back injuries forced Elke to retire from her professional tennis career in 2004.

In November 2003, she announced her engagement to Australian tennis player Lleyton Hewitt, but they ended their relationship in October 2004. She is now engaged to 27-year old Belgium-based American basketball player Brian Lynch, who is based in Clijsters' home town of Bree.

Clijsters was an accomplished junior player. In singles, she finished as runner-up in the 1998 Wimbledon junior event, placing 11th in the year-end singles ranking. In the same year in doubles, Clijsters won the French Open title with Jelena Dokic, and the US Open with Eva Dyrberg, ending the season as number four in the ITF junior doubles world ranking.

In 1999, Clijsters made her breakthrough professionally. Playing through the qualifying rounds, she made it through the main draw of Wimbledon, wherein she defeated then world number 10 Amanda Coetzer en route to the fourth round, where Clijsters lost to her childhood idol Steffi Graf. Later that summer, Clijsters reached the third round of the US Open, losing to eventual champion Serena Williams; at one stage, she had the opportunity to serve for the match. In autumn, Clijsters won her first WTA singles title at Luxembourg. She followed this up with her first WTA doubles title at Bratislava, partnering Laurence Courtois.

Clijsters climbed her way up the rankings over the next couple of years. In 2001, she reached her first Grand Slam final at the French Open, where she lost an extremely close match to Jennifer Capriati, by a score of 12-10 in the third set. Her next important breakthrough came at the end of 2002, when she won the year-end WTA Tour Championships in Los Angeles, scoring a huge win in the final over then world number one, Serena Williams, 7-5 6-3. On her way to the final, she beat then world number four Justine Henin and then world number two Venus Williams (when Williams retired).

Clijsters had her career-best season in 2003. She won nine singles tournaments and seven doubles titles (including French Open and Wimbledon) that year. Among her singles tournament runs was the defending her WTA Tour Championships title, and reaching two Grand Slam finals (French Open and US Open), losing on both occasions to Henin (now Henin-Hardenne).

On 11 August 2003, she attained the top ranking, holding the spot for 12 non-consecutive weeks before losing it later in the year to Henin-Hardenne. She is the first woman to achieve the feat without winning a Grand Slam title.

Clijsters started 2004 by reaching her fourth career Grand Slam final at the Australian Open, where she lost once more to Henin-Hardenne. She then won two consecutive titles in Paris and Antwerp. While defending her Tier I title at Indian Wells however, Clijsters began to have problems with her wrist, eventually requiring surgery and forcing her to withdraw from most tournaments. She attempted a comeback towards the end of the season, winning several matches, before reaggravating the injury.