In 2002, Stepp successfully challenged Democratic Senator Kimberly Plache for Plache's Racine County-based State Senate seat. From 2003 until 2007, Stepp served as a Republican in the Wisconsin State Senate, representing the 21st Senate district.[3] Stepp was only the second Republican to win an election in the Racine County Senate district in the previous 50 years. She announced in 2005 that she would not run for re-election in 2006, saying she wanted to devote more time to her family.[4] She was succeeded by Democrat John Lehman.[5]
In August 2017, it was announced that Stepp would be resigning to become a deputy administrator of the U.S. Environmental Protection Agency.[8] Stepp supported Trump at rallies in Wisconsin, and has questioned the existence of climate change.[9]
Stepp resigned from the EPA in January 2020, and moved to Missouri, where she worked for a clean water non-profit and an ecological restoration company. She was hired as city administrator of Branson, Missouri, in 2022.[10]