John Gregory Keyes was born in 1963, in Meridian Mississippi to Nancy Joyce Ridout and John Howard Keyes. His mother was an artist, and his father worked in college administration. When he was seven, his family spent a year living in Many Farms, Arizona, on the Navajo Reservation, where many of the ideas and interests which led Greg to become a writer and informed his work were formed.
Greg received a BA in Anthropology from Mississippi State University, and worked briefly as a contract archaeologist. In 1987 he married Dorothy Lanelle Webb (Nell) and the two moved to Athens, Georgia, where Nell pursued a degree in art while Greg ironed newspapers for a living. During this time, Greg produced several unpublished manuscripts before writing The Waterborn, his first published novel, followed by a string of original and licensed books over the following decade and a half.
Greg earned a Masters in Anthropology from the University of Georgia and completed the coursework and proposal for a PhD, which thus far remains ABD. He moved to Seattle, where Nell earned her BFA from the University of Washington, following which they moved to Savannah, Georgia. In 2005 the couple had a son, Archer, and in 2008 a daughter, Nellah. Greg continues to live with his family in Savannah, where he enjoys writing, cooking, fencing, and raising his children.
Dawn of the Planet of the Apes: Firestorm is his twentieth published novel.