Hoffman started publishing short stories in 1975. Her first nationally published short story appeared in Asimov's Science Fiction magazine in 1983. She has since published over 200 in various anthologies and magazines.
Her short story, "A Step Into Darkness" (1985), was one of the winners of the L. Ron Hubbard Writers of the Future award and was published in the first of the Writers of the Future anthologies.
Her second collection of short stories, Courting Disasters and Other Strange Affinities, was nominated for the 1992 Locus Award for best collection of the year.
Her novella '"Unmasking", published in 1992 by Axolotl Press was a finalist for the 1993 World Fantasy Award. Her novella "Haunted Humans" (seen in The Magazine of Fantasy & Science Fiction, July 1994) was a finalist for the 1995 Nebula Award for Best Novella and on the same ballot her novelette "The Skeleton Key" was shortlisted for the Nebula Award for Best Novelette. Her short story "Trophy Wives" won the 2008 Nebula Award for Best Short Story. .
Her first novel, The Thread That Binds the Bones, won the Bram Stoker Award for first novel. Other novels include The Silent Strength of Stones (a sequel to Thread), A Fistful of Sky, and A Stir of Bones. Her best known works are set in the Pacific Northwest and Southern California, and involve people (often entire families) with magical talents. The stories have invited comparison to Zenna Henderson and Ray Bradbury's stories on similar themes.
She has been shortlisted, awarded and finalist for awards for novella, novelette, novel, fantasy novel, adult literature, work for younger readers, young adult books, and children's literature for the Nebula, Locus, World Fantasy Award, the Theodore Sturgeon Award, the HOMer award from CompuServe, the Endeavour Award, the Mythopoeic Society Award, the James Tiptree Jr. Award and the Philip K. Dick Award.
Her brother is the musician Kristian Hoffman.
She lives in Eugene, Oregon with her cats. She is a member of the Wordos writers' group.