J.K. Rowling added the initial K to her pen name at her publisher’s request.
Rowling was born Joanne Rowling and did not originally have a middle name. Bloomsbury reportedly wanted the author’s name to contain two initials before the publication of Harry Potter and the Philosopher’s Stone. Rowling selected K in honor of her paternal grandmother, Kathleen Ada Bulgen Rowling.
The resulting name, J.K. Rowling, was used on the Harry Potter books. The initials helped create a pen name whose gender was not immediately obvious to some readers, a publishing approach sometimes used in children’s and genre fiction. Rowling has also published under the separate pseudonym Robert Galbraith.
The K does not stand for a middle name legally given at birth. That distinction explains why biographies often describe Rowling as Joanne Rowling while her best-known books carry the J.K. Rowling credit. The name has since become one of the most recognizable author brands in modern publishing.