Fitzsimmons was an All-American in both track and cross country at UWM. Fitzsimmons won a national championship in the two-mile run in 1985 and she was named an All-American in cross country and track in both 1985 and 1986.
After leaving UWM, Fitzsimmons remained extremely active in road racing. She finished third in the U.S. 10-Mile Championships and second in the 1997 Las Vegas Half-Marathon. She was also a part of the 1999 U.S. World Half Marathon Team. She has also claimed victory in Al's Run in Milwaukee numerous times, and has run in the 1996 and 2000 U.S. Olympic Marathon Trials. She also ran in the 2000 U.S. Olympic Track and Field Trials.