Kathy Diane Wentworth was born on January 27, 1951, in Tulsa, Oklahoma. A graduate of the University of Tulsa, Wentworth embarked on a professional writing career with the short story "Daddy's Girls", which was published in the anthology L. Ron Hubbard Presents Writers of the Future, Volume 5. (She later served as editor of the Writers of the Future contest from 2009 until her death.)

In the course of her career, Wentworth wrote over sixty short stories, three of which were nominated for the Nebula Award: "Burning Bright" in 1998, "Tall One" in 1999, and "Born-Again" in 2006. Her novelette "Kaleidoscope" was nominated for the Nebula for Best Novelette in 2009. She published her first novel, The Imperium Game in 1994, and another stand-alone novel, This Fair Land, in 2002. In addition, Wentworth wrote several novel series, including the House of Moons Chronicles ("Moonspeaker", 1994, and "House of Moons", 1995); the Heyoka Blackeagle series ("Black on Black", 1999, and "Stars Over Stars", 2001), and the two first books in the Jao Empire series, co-written with Eric Flint ("The Course of Empire", 2003, and "The Crucible of Empire", 2010).

Wentworth served as the secretary of the Science Fiction and Fantasy Writers of America (SFWA) for two terms in the early 2000s. She died of complications from cancer and pneumonia in Tulsa, on April 18, 2012.