Laura J, Mixon was born in New Mexico on December 8, 1957. She is trained as a chemical and environmental engineer, and in the 1980s served a stint in the U.S. Peace Corps in East Africa.

Mixon's first published work was the SF novel Astropilots(1987) written for the young-adult series 'Omni Odysseys'. She has also written the Avatars Dance series of novels, which include Glass Houses(1992), Proxies(1998), and Burning The Ice(1992). In 1997 she co-wrote the novel _Greenwar_with her husband, fellow SF writer Steven Gould. In 2011, Mixon published the first of a new series, Wave, under the pseudonym M.J. Locke _._The first book in the series is entitled Up Against It.

Mixon has also written several short stories, including two - "The Lamia's Tale" and "A Dose of Reality" (with Melinda M. Snodgrass) for the George R.R. Martin-edited _Wild Cards_shared universe of novels and stories.

_Up Against It_was nominated for the 2012 James Tiptree Award for Gender-Bending SF. Mixon won the 2015 Hugo Award for Best Fan Writer for her online essay "A Report on Damage Done by One Individual Under Several Names ".