J.K. Rowling’s first name is Joanne.
She was born Joanne Rowling on 31 July 1965 in Yate, Gloucestershire, England. The initial “K” was added when her first publisher asked her to use two initials, partly because the publisher believed some boys might be less likely to choose a book by a woman author. Rowling selected “Kathleen” as the additional initial in honor of her paternal grandmother, although Kathleen is not her birth name.
The author has generally been known publicly as J.K. Rowling since the publication of Harry Potter and the Philosopher’s Stone in 1997. Her legal name later changed after marriage, but her publishing name remained the same. The “J” therefore represents Joanne, while the “K” represents Kathleen.
A common mix-up is assuming that “J.K.” means the author was born with two initials. It was a publishing name created for the Harry Potter series.