She competed at two Winter Olympics (1988, 1992) and finished fourth at the 1994 World Figure Skating Championships.

After winning the national silver medal, she was assigned to her first major international event, the 1988 European Championships, and came in ninth.

Represented West Germany at the 1988 Winter Olympics in Calgary, Kielmann placed 12th in the compulsory figures, 11th in the short program, 10th in the free skate, and 10th overall.

In the 1991–92 season, Kielmann collected silver medals at the 1991 Nebelhorn Trophy, 1991 Nations Cup, and 1991 Skate Canada International.

After successfully defending her national title, she won silver at the 1992 European Championships in Lausanne and was selected to represent unified Germany at the 1992 Winter Olympics in Albertville, France.

Kielmann also competed in roller skating, winning bronze at the 1987 and 1988 World Championships and silver in 1990.