Fantasy and science fiction author Katharine Kerr was born (as Katharine Brahtin) on October 3, 1944, in Cleveland, Ohio. She never knew her father, who was killed in the Battle of the Bulge during World War II. When Kerr was an adolescent her family moved to Santa Barbara in Southern California. After briefly attending Stanford University in the early 1960s, majoring in classics, she moved to the San Francisco Bay area, where she has continued to live. She held a number of low-paying jobs after leaving Stanford, while being involved in various civil rights and feminist movements. She also read extensively in the fields of history, language, and literature, becoming a mostly self-taught scholar in medieval, especially Celtic, history. Kerr can read Latin, French, and Welsh, as well as some Spanish and Italian, but can speak only English.
Kerr became interested in fantasy role-playing games in the late 1970s, after receiving one as a gift. In the early 1980s, she entered the fantasy role-playing gaming field as a game designer for TSR, Inc., and as a contributing editor of the company's gaming magazine, Dragon Magazine, for which she wrote articles. Since the mid- 1980s, she has worked as a freelance author of medieval fantasy and science fiction novels and short fiction. She also co-edited three anthologies of fantasy short stories in the mid-1990s. She currently lives in San Francisco with her husband, Howard Kerr, whom she married in 1973.
Although born and raised in America, Kerr's family's British ancestry was a major influence in her youth; she was taught to read from British books. Her other outside interests include sports (especially baseball) and cats.