Grier returned to the Republic of Vietnam for a second combat tour in 1970. A decorated Vietnam veteran, his subsequent assignments included serving as an aviation staff officer in Washington, D.C. and a senior operations officer in Alaska. He returned to D.C. as chief of the Infantry/Armor Branch at the Military Personnel Center. A graduate of the Army War College in 1983, he served as an operations officer at Fort Ord, California, followed by a posting at Fort Monroe, Virginia where he served as director of systems management.
His final tour on active duty was as senior advisor to the Colorado Army National Guard where he served from 1987-1992. Grier was promoted to his present rank in 1993 and relinquished command in 1996.
His military awards and decorations include: the Silver Star; Legion of Merit with two Oak Leaf Clusters; Distinguished Flying Cross with three Oak Leaf Clusters; Bronze Star with two Oak Leaf Clusters; Meritorious Service Medal with four Oak Leaf Clusters; Air Medal with V Devise and Numeral 40; Army Commendation Medal; Master Parachutist Badge; Senior Army Aviator Badge; Special Forces Tab; and Army Staff Identification Badge.
Grier is retired from the Colorado Department of Local Affairs after ten years as the director of the Division of Emergency Management. He is married to the former Jan Schlumbohm of Lawton, Oklahoma, and they reside in Centennial, Colorado. They have three sons: Thomas III, Jud, and Andy; and one granddaughter, Lily Georgia.