Kate McMullan was born in 1947 in St. Louis, Missouri. She received a Bachelor's degree in elementary education at the University of Tulsa and a Master's degree in early childhood education from Ohio State University. She taught elementary school in inner-city Los Angeles and on an American Air Force base in Germany. In 1976, she moved to New York City and became an editor of language arts and audiovisual materials for a publishing house. She has written over 50 children's books under the names Kate McMullan, Katy Hall, and K. H. McMullan. The book, I Stink!, won a Boston Globe-Horn Book Honor. Nutcracker Noel and Hey, Pipsqueak, which were illustrated by her husband Jim McMullan, were… voted among the New York Times Ten Best Picture Books of the Year. She writes the Dragon Slayers' Academy series and the Fluffy, the Classroom Guinea Pig series. She also teaches at New York University's School of Continuing and Professional Studies and is a member of the faculty of the New School's MFA Writing Program.
Kate and Jim McMullan have collaborated on many popular picture books, including I’m Brave! ; I’m Fast! ; I’m Big! ; I’m Bad! ; I’m Dirty! , a Child Magazine Best Book; I’m Mighty! ; and I Stink! , a New York Times Best Illustrated Book and a Boston Globe-Horn Book Award Honor Book. The McMullans live in Sag Harbor, New York.