Kimiko started playing tennis when she entered elementary school. While a senior at Sonoda Gakuen High School in Hyogo Prefecture, Kimiko captured a triple-crown title by winning in the singles, doubles, and team competitions at the 1988 National Inter-High-School Tennis Tournament. She turned professional as soon as she graduated from high school in 1989. The following year in 1990, she achieved an incredible task of reaching 4th round at the Australian Open. At the 1993 US Open, she was a quarterfinalist, and in the following year, she won her first overseas tournament at the 1994 NSW Open in Sydney which made her the first Japanese player to achieve the top 10 WTA Ranking (ranked No. 9). In 1995 she was ranked No. 4 in the WTA Ranking. The following year in 1996, she defeated No. 1 WTA Ranking player, Steffi Graf, in the Fed Cup singles match played at the Ariake Coliseum. At the Wimbledon, the two met in the semifinals and since neither gave in to the other, the match prolonged until sunset and had to be carried over to the next day. After a hard 2-day's battle, Steffi Graf captured her place in the finals. In November of 1996, after losing to a 16 year old, Martina Hingis at the Chase Championships, Kimiko retired from the WTA Tour. She had maintained her top 10 ranking from 1994 to 1996. Her ranking was No. 9 at the time of her retirement.

In April 2008 Kimiko declared her intention to "take on a new challenge" as a professional tennis player. In the first year of her return, she won both singles and doubles at All Japan Tennis. Since then, she has proceeded to take on new challenges on world tours and in 2009, won the WTA Hansol Korea Open.