She joined the studio in 1981, starting her career as an animator on The Black Cauldron. She's the mother of Jennifer Zielinski. She was pregnant with her daughter at the time that Aladdin was made. After working on The Hunchback of Notre Dame, Kathy left Walt Disney Animation Studios and went to work for Dreamworks Animation SKG on films such as The Prince of Egypt as an animator, The Road to El Dorado as the supervising animator for the villain Tezekel Khan, an animator on the main character Spirit in Spirit: Stallion of the Cimarron, and as animator on Over the Hedge, Bee Movie, Kung Fu Panda, and The Croods. She returned to the Disney studio in late 2013, as she is credited as an animator in Frozen.