She began writing when she was nine, originally publishing under her
maiden name of Kathleen Herald.
The "M" in her professional name K M Peyton is the initial of her husband Mike who helped her create the plots of some of her books.
She was awarded the MBE (Member of the Order of the British Empire) in the 2014 Queen's New Years Honours List for her services to Children's Literature. She is a children's author in London, England.