J.K. Rowling’s first name at birth was Joanne.
She was born Joanne Rowling on 31 July 1965 at Yate General Hospital near Bristol, England, and grew up in Gloucestershire. The initial “K” in her professional name does not represent a middle name given at birth. Her publishers suggested adding an initial because they thought some boys might avoid books written by a woman.
The “K” was chosen to honour her paternal grandmother, Kathleen Ada Bulgen Rowling. Rowling has said that Kathleen was not actually her own middle name in the way the public often assumes; the initial was adopted for her author identity. She became widely known as J.K. Rowling when Harry Potter and the Philosopher’s Stone was published in 1997.
A common mix-up is treating “K” as part of Rowling’s birth name or assuming that “Joanne” is a nickname. It is her first name, while “J.K. Rowling” is the professional name used on her books.