Hanft started her theatrical career in the early 1960s during the Golden Age of experimental theater at such venues as La MaMa E.T.C. and Caffe Cino, and in a few years she became known as "the Ethel Merman of off-off Broadway" for her comedic talent. She often played eccentric, flamboyant, raunchy characters in many successful plays like Tom Eyen's Why Hanna's Skirt Won't Stay Down, The White Whore and the Bit Player (she also appeared in the Cannon Films version of the play), Areatha in the Ice Palace, My Next Husband Will Be a Beauty, Give My Regards to Off Off Broadway, Women Behind Bars, Italian American Reconciliation, and The Neon Woman (the last co-starring Divine). She had great success in the David Rabe play In the Boom Boom Room at Joseph Papp's Public Theater. She appeared in many Off-Off Broadway plays by Tom Eyen. and Stephen Holt. She appeared in "The Dirty Little Girl with the Paper Flower in Her Hair Is Demented", "Who Killed My Bald Sister Sophie", "Reety in Hell", "The Kitty Glitter Story", "Stoop", "Bambi Levine, Please Shut Up!", and as Judy Garland dying in her bathroom in "London Loo". She appeared as herself in two documentary features, Beautiful Darling about Candy Darlng, and I Am Divine, about the life of the performer Divine.