Grunert was sent to France as an observer with British forces in 1917 during World War I. During the American build up, he served as assistant chief of staff for I Corps and was awarded the Army Distinguished Service Medal for his work during the United States offensives of 1918. The citation for the medal reads:
The President of the United States of America, authorized by Act of Congress, July 9, 1918, takes pleasure in presenting the Army Distinguished Service Medal to Lieutenant Colonel (Cavalry) George Grunert, United States Army, for exceptionally meritorious and distinguished services to the Government of the United States, in a duty of great responsibility during World War I. With remarkable skill, constantly displaying zeal and high military attainments, Lieutenant Colonel Grunert performed his exacting duties as Assistant Chief of Staff, G-1, of the 1st Corps, during the successive operations at Chateau-Thierry, on the Ourcq and Vesle, and in the St. Mihiel and Argonne-Meuse offensives. By his untiring and painstaking efforts and unusual ability he performed the most difficult tasks, rendering services of great value to the Government.[2]
After a second tour of duty in the office of the Army Chief of Staff, Grunert attended the Command and General Staff School at Fort Leavenworth in Kansas from 1930 to 1932. In 1933, he was the director of military intelligence and espionage division course at the Army War College and in 1935, he became director of war plans division course.
In November 1938 Grunert succeeded George C. Marshall in command of 5th Brigade at Vancouver Barracks, Washington. Grunert was promoted to major general in 1939 and, in October, returned to the Philippines to command the Philippine Division. From May 1940 to November 1941 Grunert commanded the Philippine Department, directing the United States Army supervision and control over the Philippine defense force until Douglas MacArthur came out of retirement to assume command in July 1941. MacArthur abolished the Philippine Department as a redundant command echelon in November 1941 and Grunert returned to the United States.
World War II
The Japanese attack on Pearl Harbor occurred shortly after Grunert reached the United States, and he was shuffled between a number of assignments that included command of the Sixth Service Command at Fort Sheridan, Illinois, serving as the ranking military officer in the Chicago area, and two administrative posts with Army Service Forces as Deputy Chief of Staff for Service Commands (Service of Supply) overseeing the nine United States-based supply and logistics commands (formerly corps areas), under General Brehon B. Somervell.
Grunert held interim command over the First Army until January 1944 while Lieutenant General Omar Bradley completed assembling and staffing its new headquarters in England for the Normandy landings. Grunert continued command of Eastern Defense Command, which also assumed the duties of Central Defense Command, and Second Service Command for the New York area until his retirement in July 1945.
Pearl Harbor investigation
In June 1944, Grunert was appointed by Secretary of War Henry Stimson as the presiding officer of a secret panel that investigated the army response to events prior to the attack on Pearl Harbor. The Pearl Harbor Board report, released after the war, traced the entire military and diplomatic history prior to the attack finding much fault along the way, critical of break downs in communications between Secretary of State Cordell Hull, George C. Marshall and a failure of appropriate action by Hawaiian Department commander, Walter C. Short. The panel's method of investigation and conclusions are still subject to criticism today.
Retirement
Grunert died at Brooke Army Hospital in San Antonio, Texas, on January 12, 1971, at age 89 and was buried at Fort Sam Houston National Cemetery. He was survived by his wife Florence Reynolds, daughter Mary and son-in-law, then First United States Army commander, Lieutenant General Jonathan O. Seaman at Fort Meade, Maryland. His son, Colonel George R. Grunert, attended the United States Military Academy, graduating with the class of 1930 and played on the army polo team. He was a veteran of World War II and Korea and preceded his father in death.
Decorations
Ribbon bar with the list of General George Grunert's decorations:[3]