J.K. Rowling’s first name is Joanne.
She was born Joanne Rowling on 31 July 1965 in Yate, Gloucestershire, England. The initials in her author name do not represent a full two-part given name: the “J” comes from Joanne, while the “K” was chosen in honor of her grandmother Kathleen.
Rowling adopted the name J.K. Rowling when Harry Potter and the Philosopher’s Stone was prepared for publication. Her publisher believed that some boys might be reluctant to buy a fantasy novel written by a woman, so a gender-neutral presentation was used. Rowling did not originally have a middle name of her own; Kathleen was added for the pen name.
The initials are therefore a branding choice as well as a personal reference. They should not be confused with “Jo,” a nickname Rowling has also used publicly, or with Robert Galbraith, the pseudonym she later used for crime fiction.