As a single mother with her parents help, she obtained a degree in both English and history from the University of Wisconsin–La Crosse.[2] During her college years, she was a sorority member of Alpha Delta Pi.[3] After graduation, she became an English professor at the University of Wisconsin–Eau Claire alongside her husband Harry.[4] However, when she became pregnant she was denied maternity leave. She fought this and overturned the policy across the entire UW system. In 1971, Harder became a founding member of the National Organization for Women in Wisconsin.[5] She later became an advisor for older students at the University of Wisconsin-Eau Claire.[6] In 1975, she was appointed assistant to the chancellor for affirmative action and educational opportunities at the University of Wisconsin-Eau Claire.[7] She was the first Title IX officer at the University of Wisconsin, Eau Claire.[8] At the conclusion of the 1970s, Harder was a key figure in creating the Wisconsin Women's Network.[4] During her lengthy career at the university, Harder founded the women's studies program, which she later Chaired.[5]
In 1983, Harder was appointed convener of the Wisconsin Women's Council, and two years later was elected president of the American Association of University Women (AAUW).[9] The Wisconsin Women's Council was composed of 15 women selected by Anthony Earl to address, amongst other topics, women in poverty.[10] In 1985, Harder and Irene Natividad were elected co-presidents of the Council of Presidents (CP) of the National Council of Women's Organizations.[11] That year, she was also invited to the United Nation's sponsored women's forum in Nairobi, Kenya.[12] Her term as president lasted until 1989, when she was replaced by Sharon Schuster.[13] While she served her term as president, Harder also chaired their Educational Foundation and was vice-president of the International Federation of University Women.[14]
After leaving the AAUW, Harder became active in the National Peace Foundation (NPF).[15] She was also elected president of the NGO Women for a Meaningful Summit in 1988.[16] With the NPF, she helped manage the Open World Programme, which was launched in 1999, which aimed to bring together 5 thousand Russian leaders to learn about the USA's free enterprise system. She was elected president of NPF in 2006.[15] In 1991, she and Mike Blanchard co-chaired the Education for Employment Council in Wisconsin.[17]
In February 2013, Harder and her husband were named Professor Emerita of the University of Wisconsin–Eau Claire.[18]