Sagal began her career working the Hollywood circuit. She appeared in several television movies between 1971 and 1975 including the Columbo picture "Candidate for Crime" in 1973 working as a back-up singer for various mega-stars including Bob Dylan, Gene Simmons, and Tanya Tucker. She was plucked from relative obscurity by Bette Midler, who hired her for her 1979 tour as one of her back-up band (The Harlettes).
Sagal returned to television in 1985 in the failed television series Mary starring Mary Tyler Moore. This led to her being cast in her most well-known role, that of Peg Bundy on the very successul American sitcom Married...with Children. On the show she portrayed a lower-class, unhappy, sex-craved wife of a shoe salesman. Her career focused almost entirely around this series for its ten year run until 1997 (with the exception of several other television movies.)
After the end of Married...with Children, several more television movies folllowed for Sagal, and she was also a featured voice on the children's cartoon Recess. Then in 1999 Matt Groening, who created The Simpsons, cast her as one-eyed alien spaceship pilot Leela in his sci-fi cartoon comedy Futurama The show developed a cult following but was cancelled four years later. No sooner had that door closed than she had been cast as the wife of John Ritter in the sitcom 8 Simple Rules for Dating My Teenage Daughter in 2002.
Sagal is also an accomplished songwriter. In 1996 she released a gold selling album of original material and covers called "After the Harvest."