Sharon Creech was born in South Euclid, Ohio to parents Ann and Arvel Creech. She describes her childhood home as "noisy and rowdy" and cites her family-oriented upbringing in South Euclid as the primary inspiration for the Finney family, members of which appear as secondary characters in her 1994 book Walk Two Moons and who are the subjects of her 1990 novel, Absolutely Normal Chaos. Creech also spent a significant amount of time in Quincy, Kentucky, where she has relatives who live on a farm much like the Hiddles' farm in Bybanks, Kentucky in Walk Two Moons. Creech has stated that the town of Bybanks, which features in several of her novels, is a fictionalization of Quincy.
Creech studied literature in college as an undergraduate and graduate student. She went on to teach literature and writing in England and Switzerland. She published two adult novels in England, The Recital and Nickel Malley, before starting to write young-adult fiction. Her time in the classroom teaching literature to young people influences her writing; a common theme in her fiction and poetry is a youthful resistance to literature that almost always turns out to be generative. Creech demonstrates the utility of reading and writing as an emotional outlet for young people in works such as Walk Two Moons, Love That Dog, Absolutely Normal Chaos, and more.
Creech spent eighteen years abroad before returning to the United States in 1998. In 1995, she won the Newbery Medal from the American Library Association for the first of her novels to be published in the US, Walk Two Moons. She has since won the IRA/CBC Children's Choices award in 1999 for Bloomability, the Parents' Choice Award, USA, in 2000, and the Newbery Honor Award in 2001 for The Wanderer, the 2001 YALSA Popular Paperbacks for Young Adults award for Absolutely Normal Chaos, and the 2002 Carnegie Medal for Ruby Holler.
Creech currently lives in Maine with her husband, Lyle Rigg.