Born into a farming and ranching family in Winters, Texas in 1949, Bill Modisett began writing in his early teens and has continued to this day. Authors who influenced his early work included Hal Borland (When the Legends Die) and Ernest Hemingway (For Whom the Bell Tolls and The Old Man and the Sea). Later, Modisett met nonfiction author J. Evetts Haley (A Texan looks at Lyndon and Charles Goodnight: Cowman and Plainsman), and novelist Elmer Kelton (The Good Old Boys and The Time It Never Rained) and they heavily influenced his writing.

Throughout his work life, Modisett has made a living as a newspaper reporter and editor. He was employed 10 years by the San Angelo Standard Times, 22 years as editorial page editor of the Midland Reporter-Telegram; three and a half years as business writer for the Odessa American, three and a half years as editor of the Monahans News and two years as editor of the Polk County Enterprise in Livingston, Texas.

The strongest influences in his life were exerted by his parents, Doc and Dorothy Nell Modisett; his wife, Kimberly Modisett; his father-in-law, Vernon Honea; and close friends and subjects of two of his biographies, J. Evetts Haley and Rosalind Kress Haley. Haley was an author who insisted on  the truth as the hallmark of his books. Rosalind Haley, his second wife, used the motto "Find the truth and make it known" as the guiding principle in her work. Modisett now has adopted that motto as his own.

Modisett has authored four books: J. Evetts Haley: A True Texas Legend; Historic Midland: An Illustrated History of Midland County, Texas; An American Masterpiece: Memories of Rosalind Kress Haley; and The King of Monument: Life and Times of Henry Clay McGonagill (unpublished).

Modisett and his wife have three children, Tammy Dombroski of Eldorado, Texas; Chris Modisett and Claire Modisett, both of Midland, Texas; and four grandchildren.