Kaczmarek, a Polish American, majored in theater at the University of Wisconsin-Madison. She later studied at the Yale School of Drama for her graduate degree and was a part of its theater company. She has had several Broadway hits, including Lost In Yonkers and Raised In Captivity, where she won an LA Drama Critics’ Award. Her first television role was that of Margie Spoletto on For Lovers Read more...

In 2000, Kaczmarek was cast to play Lois in the FOX mid-season replacement Malcolm in the Middle.

This role proved to be a wise career choice for Kaczmarek, as the show was a hit and made Lois a household name. TV Guide dubbed her a "true breakout; a female Homer Simpson", and critics hailed her for her comic talents. Later, Kaczmarek would credit the show for bringing out her comedic side, Read more...

Following the cancellation of Malcolm in the Middle, Kaczmarek went on to star in the short-lived series Help Me Help You co-starring Ted Danson.

Starting Fall 2008, she will star in the hour long TNT series Raising the Bar as a judge.