She served 12 years in the Wisconsin State Assembly, representing Madison's south side.
[1] In 1983m Munts became the Co-Chair of the Wisconsin Legislature's very powerful Joint Committee on Finance -- the first woman to achieve that status.
In 1995, Munts became the Co-Chair of Common Cause Wisconsin with former moderate Republican strategist Bill Kraus.
She advocated for stronger campaign finance reform and stronger ethics legislation—including the prosecution for felony misconduct in public office of Wisconsin legislative leaders Scott Jensen (R), Chuck Chvala (D), Brian Burke(D), and Steven Foti (R) during the infamous 2001-2002 Wisconsin Legislative Caucus Scandal.
Mary Lou Munts is remembered as one of the most effective and admired Dane County state legislators and public figures.