He was trained at Fort Benning, Georgia, then went to Vietnam, where he served with the 1st ARVN Division, and the 1st Signal Brigade at Khe Sanh during the 1971 Laotion invasion.
He was honored with the Bronze Star and the Army Commendation Medal with Oak Leaf Cluster for his actions at Khe Sanh.
[2] Deciding to pursue a civilian career in law, Thornbrugh earned a Juris Doctor degree from the University of Tulsa in 1974, followed by an opportunity to work on the Washington staff of Senator Dewey Bartlett.
Thornbrugh's legal career is notable for at least two reasons: One, his colleagues and peers voted him Trial Judge of the Year in 2011; Second, he discovered that the defendant in one case (Helmerich & Payne) had substantially underreported its interest and profits, allowing the defendant to withhold millions of dollars from royalty owners and investors.
[2] A notable decision made by Judge Thornbrugh in 2009, occurred during review of a case between Tulsa-based energy services company, Helmerich & Payne (H&P), and oil royalty owners in Beckham County, Oklahoma, in which the trial court had ordered H&P to pay the royalty owners $68.5 million in damages.
[c] The judgement was appealed, and came before Judge Thornbrugh, who determined that the previous award was erroneous because, "... the jury had under-calculated the amount of interest and profits the energy company had made."
[4] Governor Mary Fallin appointed Judge Thornbrugh to fill a vacancy on the Oklahoma Court of Civil Appeals in September 2011.