Shawna McCarthy began her publishing career at Firehouse Magazine as an editorial assistant and moved up to editor before switching genres by becoming assistant to the editor at Asimov's. She took over as editor in 1983 and won the professional editor Hugo, and was a finalist for 1984 and 1985; she was an SF Chronicle finalist the first two years and winner the third, and a World Fantasy finalist (Special Award—Professional) for 1984. While there, she edited for Dial the Isaac Asimov's anthologies Wonders of the World (with Kathleen Moloney, 1982), Aliens and Outworlders (1983), Space of Her Own (1984), and Fantasy! (1985). She next became a Senior Editor at Bantam Spectra, where she acquired books from writers such as Robert Charles Wilson, Connie Willis, and William Gibson, was a World Fantasy finalist for 1987, and edited Full Spectrum (1988) with Lou Aronica and Full Spectrum 2 (1989) with Aronica, Amy Stout, and Patrick LoBrutto, Locus winner and finalist respectively.

After some time off for the birth of her first child, she went back to work at Workman Publishing as Senior Editor, acquiring their only novel—Neil Gaiman and Terry Pratchett's Good Omens. Four years later, after another child, she began a new career as a literary agent with Scoville Chichak Galen while at the same time founding Realms of Fantasy Magazine with Sovereign Media of Virginia. Realms was for 16 years the world's most successful magazine devoted solely to fantasy; new publisher Damnation Press kept it alive for nearly a year, but produced its final issue last October. She was again a World Fantasy Special Award—Professional finalist for 2007. As an independent agent for more than ten years, she represents Robert Charles Wilson, Daniel Abraham, Eric Flint, Liz Williams, Sarah Zettel and many other well-known fantasy and science fiction writers. She resides in coastal New Jersey.