He has written novels, short fiction, screen plays for television, scripts for comic books, animation, newspaper copy, and magazine articles.
Barnes's first published piece of fiction, the 1979 novelette "The Locusts", was written with Larry Niven, and was a Hugo Award nominee.
Together with his wife, Tananarive Due, and actor Blair Underwood, Barnes won the 2009 NAACP Image Award for outstanding Literary Work - Fiction for In the Night of the Heat: A Tennyson Hardwick Novel.
They also taught a course together at UCLA called "The Sunken Place: Racism, Survival & Black Horror" that experienced a surprise visit from Get Out director Jordan Peele.
He is an advanced student in Jun Fan kickboxing (Bruce Lee method under Dan Inosanto), and is an instructor in Wu-style tai chi under Hawkins Cheung.