Pehl was one of the writers on MST3K. From 1992 to 1996, Pehl played the role of "Magic Voice", a woman's voice who would announce upcoming commercials at the beginning of the show. In 1996, she began playing the role of Pearl Forrester, the mother of Dr. Clayton Forrester, initially as a guest character and then as a recurring character on the departure of TV's Frank. When Beaulieu left the series at the end of the seventh season, she took over as the head "mad" on the series. She would retain that role to the show's end in the tenth season. Pehl also played a number of other small roles on the series, such as "Jan in the Pan", a woman's head that had been removed from a body, and "White Trash Party Girl" from the MST3K episode 517 "Beginning of The End". In the Bonus Features of the DVD release of Leech Woman, as part of the larger, special release of the 25th Anniversary Edition, Pehl is featured in an ongoing series, Life After MST3K.
Work after ''MST3K''
Since the ending of the series, Pehl has had comedy segments on National Public Radio. In 2007, she returned to MST3K-style riffing on bad movies, joining former castmate Mike Nelson's RiffTrax for the film Glitter, and Bill Corbett for The X-Files movie, as well as becoming a cast member on Joel Hodgson's Cinematic Titanic, making her one of a select few MST3K alumni to be involved with both Mike and Joel's successor projects. After an extended stay in New York City, she moved to Austin, Texas with her husband Ronald DeGroot in 2007, and has performed with the Violet Crown Radio Players. She has since starred in the science fiction computer game as both Captain Beth Ingram of the Starship Bridgebuilder and the voice of the computer Westwick Main. Pehl appeared on Ken Reid's TV Guidance Counselor podcast on May 13, 2016.
Cinematic Titanic and Rifftrax
On October 30, 2007, Joel Hodgson announced he was starting a new show with the same "riffing on bad movies" premise as MST3K called Cinematic Titanic, together with former MST3K cast and crew members Pehl, Trace Beaulieu, J. Elvis Weinstein, and Frank Conniff. She continued to tour with Cinematic Titanic starting from November 2012 until the show's indefinite hiatus in December 2013. In June 2015, Pehl teamed up with Bridget Jones Nelson to regularly riff shorts for RiffTrax, and participated in the RiffTrax Live MST3K reunion show that was broadcast live in theaters throughout the United States and Canada on June 28, 2016.
Literary work
Pehl wrote her first book in 2004 I Lived with My Parents and Other Tales of Terror published by Plan 9 Publishing. Pehl contributed quotes to Girls Against Girls by author Bonnie Burton. Pehl has stated that she is a Catholic, and has written for the Catholic Digest, including an article about a priest who works in a circus. In 2011, Pehl released the book "Employee of The Month And Other Big Deals."