Jenna McMahon began her show business career as an actor on television in the late 1950s, appearing in small parts on the rascally comedy "Dennis the Menace" and the seminally eerie suspense anthology "The Twilight Zone". Her work was sporadic until the early 1970s, when she both appeared on and wrote an episode for the uproarious "The Bob Newhart Show". As there were few female comedy writers in television at the time, she naturally gravitated to shows featuring women performers and began to concentrate almost exclusively on her writing. Work on such progressive sitcoms and sketch shows as "Mary Tyler Moore", "Maude", "The Carol Burnett Show", and Erma Bombeck's TV movie "The Grass is Always Greener Over the Septic Tank", solidified her as a voice for television comediennes. She started to get into producing in the 1980s with an episode of "Soap", of which she also penned 11 episodes. Her partnership with Vicki Lawrence on "The Carol Burnett Show" led to work on the star's spin-off sitcom, "Mama's Family". During this time, she also wrote for the girl-centric boarding-school sitcom "The Facts of Life". Always one to thrive with past collaborators, McMahon assisted in writing a 1987 special for Burnett (in tandem with Whoopi Goldberg, Carl Reiner, and Robin Williams) and was the creator of the two-hour "Facts of Life Reunion" in 2001.