Justin Matthews Glenn was born in Little Rock, Arkansas, and raised in Glendale and Phoenix, Arizona. He graduated from Stanford University [B.A., Classics, 1967; magna cum laude, Phi Beta Kappa] and was a Woodrow Wilson Fellow at Princeton University [M.A., Classics, 1969; Ph.D., Classics, 1970]. He was a professor of Classics at the University of Georgia and Florida State University for 35 years, and he has published 70 articles, notes, and reviews in his field. His fascination with American history was kindled as a young boy when he first held a treasured family heirloom, the pistol his great-grandfather had carried as a Confederate captain.

In 1974 he discovered his genealogical connection to the Washington family. About that same time, without realizing it at first, he began researching his book "The Washingtons: A Family History." Initially he set out to collect as many cousins as he could—descendants of his ancestor Nathaniel Pope, whose daughter Anne married the immigrant John Washington and became the great-grandmother of President George Washington. In 1992 Glenn made contact with John Augustine Washington, the leading authority on the Washington family and later Genealogist of The National Society of the Washington Family Descendants. John generously provided invaluable help and guidance, along with exclusive publishing rights to draw freely from his voluminous unpublished files on the Washingtons.

Eventually Glenn collected over 63,000 direct descendants of the immigrant John Washington. A true family history and not simply a bare bones genealogy, his book incorporates over 1,200 detailed biographical sketches. This comprehensive history is being published initially in a nine-volume Kindle edition by Savas Beatie. A hardcover edition eventually will appear in nine volumes plus a one volume General Index, with four of the volumes being published in two parts. Volumes one and two form a set, with a cumulative bibliography at the end of volume two. The other volumes have individual bibliographies. "The Washingtons" includes the time-honored but now controversial John Wright line, which recently has been challenged largely on the basis of DNA evidence.

Now retired, Glenn resides with his wife Jody in Tallahassee, Florida. Since 2002 he has served as Registrar General of The National Society of the Washington Family Descendants.