To heighten his understanding of, and appreciation for, what the World War II combat soldier went through, he became involved in World War II re-enactment groups, in which he has been active for over 35 years. As a tribute to his father, he founded the 10th Mountain Division Living History Display Group in 1983 (www.tenthmountain.org). He has served on the 10th Mountain Division Board of Directors and is on the Board of Directors of the Broomfield (Colorado) Veterans Memorial Museum.
From 2010 until 2023, Flint was the editor of WWII Quarterly magazine.
Flint Whitlock lives in Denver, Colorado, with his wife, Dr. Mary Ann Watson, a clinical psychologist and professor of psychology at Metropolitan State College of Denver. They have three grown children: Gillian Lee Whitlock, an actress and make-up artist in Hollywood; Suki Montgomery Hall, a clinical psychologist in Ithaca, New York; and Matthew Montgomery, an anesthesiologist in Denver.