Delia Sherman was born in Tokyo, Japan, and brought up in New York City. She has spent a good portion of her life in schools of one kind or another: Vassar College for undergrad, then Brown University where she earned a Ph.D. in Renaissance Studies. While she was writing her dissertation, she started teaching, first at Boston University, where she taught Freshman Composition and Fantasy as Literature, and then at Northeastern University, where she was a Lecturer in Composition.

While she was teaching, she taught herself how to write fiction. Her first story appeared in Fantasy Macabre in 1985. She broke into the Big Time in 1988, when stories in The Magazine of Fantasy and Science Fiction and a novel, Through a Brazen Mirror, led to a 1990 nomination for the Campbell Award for Best New SF Writer. Her second novel, the historical The Porcelain Dove, was listed in New York Times Notable Books, and won the Mythopoeic Award in 1994.

Delia's short fiction for adults has appeared most recently in the anthologies Naked City and Queen Victoria's Book of Spells. Stories for YA readers have appeared in numerous anthologies, including Steampunk! and Under My Hat. "CATNYP," a story of a magical New York Between, inspired her first novel for children, Changeling. The sequel, The Magic Mirror of the Mermaid Queen, followed in 2009. The Freedom Maze, a time-travel fantasy set in Louisiana, was published by Big Mouth Press in 2011 and was awarded the Norton Award, the Prometheus Award, and the Mythopoeic Award.

Delia has judged the Crawford Award for Best First Fantasy Novel, The James Tiptree, Jr. Award, and the World Fantasy Award. She has served on the Motherboard of the James Tiptree Jr. Award, and is a founding member and past officer of the Interstitial Arts Foundation. She has worked as a contributing editor for Tor Books and has co-edited the fantasy anthology The Horns of Elfland with Ellen Kushner and Donald G. Keller, as well as The Essential Bordertown with Terri Windling, as well as two anthologies of Interstitial fiction, Interfictions 1, with Theodora Goss and Interfictions 2, with Christopher Barzak. She continues to teach SF and Fantasy writing, including at Odyssey: the Fantasy Writing Workshop, the Clarion Science Fiction & Fantasy Writers' Workshop, the Hollins University Master's Program in Children's Literature, and workshops at colleges and science fiction conventions all over America.

Delia lives with fellow author Ellen Kushner in a rambling apartment on the Upper West Side of New York City. She is a social rather than a solitary writer, and can work anywhere, which is a good thing because she loves to travel, and if she couldn't write on airplanes and in noisy caf├ęs, she'd never get anything done.