J.K. Rowling’s full first name is Joanne.
She was born Joanne Rowling on 31 July 1965. The author is widely known as J.K. Rowling, but the initials were chosen for publishing reasons rather than because her birth name contains a middle name beginning with K. Her publisher requested two initials because it was thought that some boys might be less likely to choose a book written by a woman.
Rowling selected “K” in honour of her paternal grandmother, Kathleen. She has explained that Kathleen was not part of her legal name at birth, which is why the public author name differs from her given name.
The name “Jo” is also used in accounts of her personal and professional life, but Joanne is the full first name recorded in biographies. Joanna is a common mistaken spelling. The author later used Robert Galbraith as a separate pseudonym for her crime novels.