His military education includes the Infantry Officer Basic Course, the Basic and Advanced Courses at the Judge Advocate General's School, the United States Army Command and General Staff College, and the Industrial College of the Armed Forces, National Defense University.

Earlier in his career he served in Vietnam as the Staff Judge Advocate of the 1st Cavalry Division.

Returning to the United States, he served as Deputy and later as Chief of the Government Appellate Division of the U.S. Army Judiciary.

Following attendance at the Industrial College of the Armed Forces, Holdaway served as Staff Judge Advocate of VII U.S.

[2] His younger twin brother Donald, a retired United States Air Force lawyer, died in 2016.