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 HubbardWriters 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 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 Award, the James Tiptree Jr. Award and the Philip K. Dick Award.
She lives in Eugene, Oregon. She is a member of the Wordos writers' group. In 2017, she competed in the SLUG Queen pageant in the persona of country singer "Patsy Slugtana".
As of 2020, she teaches small classes in science fiction, fantasy, and horror writing via Zoom for the Fairfield County Writers' Studio.