Career
She began performing on The Muppet Show in its third season, primarily as Gaffer the Backstage Cat. She also voice directed Dog City for Nelvana, worked as a designer for The Muppet Movie, a performing assistant for Yoda on The Empire Strikes Back, and was one of the creators of Between the Lions. While reprising Gaffer for several Muppet movies, she also performed Mokey Fraggle and Cotterpin Doozer on Henson"s Fraggle Rock.
She performed the Gelfling Kira in the movie The Dark Crystal, Allegra on Allegra"s Window, and Leona the Lion on Between the Lions.
In the film, "The Story of the Little Carpet Boy," one puppet loses several limbs before he learns to avoid land mines completely. Kathy and Michael picked up the idea from Johnie McGlade, an emergency aid worker who used a scruffy rabbit puppet to bring smiles to the faces of people who had lived through earthquakes, hunger, or genocide.
In 2013, Kathryn Mullen attended Dragon Con with Karen Prell and Michael K. as part of the 30th Anniversary of Fraggle Rock where Kathryn Mullen performed Mokey Fraggle while Karen Prell performed Red Fraggle.