Wilhelm was born in
Schmalkalden, then
East Germany (now in the Federal State of
Thuringia,
Germany). She started training
cross-country skiing as a child in 1983 and was a member of the German cross-country ski team at the
1998 Nagano Olympic Games. In 1999, while attending the
Military World Games, she came into contact with
biathlon and was hooked on the sport. Her decision to switch to biathlon proved to be a good one. The next year she experienced her first successes including a
World Cup victory. During the
Salt Lake City Olympic Games in, she was the most decorated female biathlete, winning gold medals in the 7.5 km sprint and the 4 × 6 km relay. She also won a silver medal in the 10 km pursuit. After two years of struggling, she finally moved to
Ruhpolding, Bavaria in 2004. She regained her strength and placed second in the 2004–05 World Cup season, defeated only by Frenchwoman
Sandrine Bailly. At the
2006 Winter Olympics in
Turin, she carried the German flag at the opening ceremony. After winning her third Olympic gold medal in the 10 km pursuit as well as silver in the mass start and with the German relay, she became the best female biathlete at the Olympics ever. Moreover, she dominated the 2005–06 World Cup season, winning six races and the overall World Cup trophy. She was elected "biathlete of the year 2006" as well as "German sportswoman of the year 2006". In total she has 21
IBU Biathlon World Cup wins. In the
2006–07 World Cup season, she finished second for the overall World Cup title behind teammate
Andrea Henkel. In the
2008–09 World Cup season, she finished second for the overall World Cup title behind
Helena Jonsson, with both biathletes scoring 952 points. Jonsson was awarded the overall title by virtue of her four World Cup victories against Wilhelm's three. The German media gave her the nickname
"Rotkäppchen" (
Little Red Riding Hood) because of her characteristic red hair and the red cap she uses in competition. She was able to translate her Olympic victories into multiple endorsement deals, including print and television advertising. Wilhelm announced her retirement from biathlon on 9 March 2010 so that she could focus on her studies. She took part in the International biathlon competition on the "Prize in memory of Vitaly Fatyanov", Kamchatka 2010. The event was held in
Kamchatka,
Russia on 15–17 April, where Kati came 3rd in Sprint and won a Pursuit race. In 2004, Wilhelm was a delegate to the
Federal Convention for the
Social Democrats. Wilhelm retired as an athlete after the
2009–10 season. ==Biathlon achievements==