The author of twenty-three books, he also served as a television reporter, editor, news and information officer, university press director, freelance writer, biographer, and historian.
As a boy growing up in the farm town of Decatur, Illinois, Walker was inspired by the writings of Jack London, and has written extensively about the author.
Walker's freelance writing career began in earnest in 1960 while a college student working part-time at a television reporting job in El Paso.
His first big break came in 1967 when his mentor, the late Richard O'Connor, invited him to collaborate on a biography of radical journalist John Reed.
His book, Mary Edwards Walker: Above and Beyond (2005) is a biography of the Civil War, his The Boys of '98: Theodore Roosevelt and the Rough Riders (1998) received high praise as had his Bear Flag Rising: The Conquest of California (1999), which told of events that led to the annexation of California in 1846 when the territory was a Mexican province, and Pacific Destiny: The Three-Century Journey to the Oregon Country (2000), which won a Spur Award from Western Writers of America, as had three additional Walker works.