Gasteyer developed comedy experience with the Los Angeles improv – sketch comedy group The Groundlings. She played small roles on "Seinfeld" (as a doomed customer of The Soup Nazi), as well as on the shows "Party of Five", "Frasier", "Hope & Gloria" and "NYPD Blue". In 1996, Gasteyer joined the cast of "Saturday Night Live." Among her most popular characters were high school music teacher Bobbie Mohan-Culp, National Public Radio "Delicious Dish" host Margaret Jo McCullen, Lilith Fair feminist singer Cinder Calhoun, and her impressions of Martha Stewart and Celine Dion. In 2000, she and Chris Parnell auditioned to succeed Colin Quinn as co-anchors of the news parody segment "Weekend Update", but the positions ultimately went to Tina Fey and Jimmy Fallon.