Born in her mother's hometown of Warren, Ohio, Robin McKinley grew up an only child with a father in the United States Navy. According to her, she moved around frequently as a child and read copiously; she credits this background with the inspiration for her stories. Her passion for reading was one of the most constant things in her childhood, so she began to remember events, places, and time periods by what books she read where. For example, she read Andrew Lang's Blue Fairy Book for the first time in California; The Chronicles of Narnia for the first time in New York; The Lord of the Rings for the first time in Japan; The Once and Future King for the first time in Maine. She still uses books to keep track of her life.

McKinley attended Gould Academy, a preparatory school in Bethel, Maine, and Dickinson College in 1970-1972. In 1975, she graduated summa cum laude from Bowdoin College. In 1978, her first novel, Beauty, was accepted by the first publisher she sent it to, and she began her writing career, at age 26. At the time she was living in Brunswick, Maine. She has lived in Boston and on a horse farm in eastern Massachusetts, Staten Island and Manhattan, Blue Hill, Maine and since 1991 lives in Hampshire, England, with her husband, writer Peter Dickinson and two whippet crosses.

Over the years she has worked as an editor and transcriber (1972—73), research assistant (1976—77), bookstore clerk (1978), teacher and counselor (1978—79), editorial assistant (1979—81), barn manager (1981—82; a horse fell on her hand, delaying The Blue Sword by six weeks), free-lance editor (1982—85; during this time she broke her ankle, expediting the finish of Hero), and full-time writer. Other than books she counts as her major preoccupations grand opera and long walks, both of which she claims keep the blood flowing and the imagination limber.

The heroines in McKinley's books reflect certain qualities that she saw in herself as a young woman: clumsiness, plainness, bookishness, and disinterest in the usual social games that involve flirting and dating (she says, "I didn't discover boys because they didn't discover me, and because their standards of discovery seemed to me too odd to be aspired to... they were the ones who got to have adventures, while we got to -- well, not have adventures.") She believes now that most girls go through a time growing up when they believe they must have an innate greatness and destiny beyond the apparent; that they are in fact lost princesses, switched at birth.

She writes about strong heroines because she feels very strongly about the potential for girls to be "doing things" and she feels that the selection of fantasy literature featuring girls is scarce and unsatisfactory. According to biographer Marilyn H. Karrenbrock, "McKinley's females do not simper; they do not betray their own nature to win a man's approval. But neither do they take love lightly or put their own desires before anything else. In McKinley's books, the romance, like the adventure, is based upon ideals of faithfulness, duty, and honor."

As far as her writing goes, McKinley describes herself as a "scribe" and "Damar's historian", because the stories "happen to her" and she is only responsible for writing them down. The stories of Damar have been occurring to her since before she wrote Beauty, and The Blue Sword was intended to be the first of a series about this land. Her first two books, The Blue Sword and The Hero and the Crown, are both set there, as are her contribution to the Imaginary Lands anthology and the stories in A Knot in the Grain. She has also written several retellings of fairy tales; Beauty and Rose Daughter are both versions of Beauty and the Beast, Spindle's End is the story of Sleeping Beauty, and Deerskin and two of the stories in The Door in the Hedge are based on other folk-tales.

Damar

• The Blue Sword (1982)
• The Hero and the Crown (1984)

Traditional folk and fairy tales

• Beauty (1978)
• The Door in the Hedge (1981)
• The Outlaws of Sherwood (1988)
• Deerskin (1993)
• Rose Daughter (1997)
• Spindle's End (2000)

Other stories

• Imaginary Lands (1985) (ed.) ISBN 978-0441366941
• Rowan (1992) illus. Donna Ruff
• A Knot in the Grain and Other Stories (1996)
• The Stone Fey (1998) illus. John Clapp (reprint of short story from Imaginary Lands)
• Tales of Elemental Spirits (2002) (with Peter Dickinson)
• Sunshine (2003)
• Dragonhaven (2007)
• Chalice (2008)
• Tales of Elemental Spirits (2009) (with Peter Dickinson)
• Pegasus (2010)