[3] Brooks began his military career in June 1915 as a captain with the 1st Cavalry Regiment of the Vermont National Guard, a position he held until July 1916.

At that post he was assigned to the 3rd Field Artillery Brigade in command of a detachment (later G-3) that sailed for France to reinforce the American Expeditionary Forces (AEF) in April 1918.

On October 5, 1918, during the fighting in the Meuse–Argonne, he earned a Distinguished Service Cross (DSC), the citation for which reads: The President of the United States of America, authorized by Act of Congress, July 9, 1918, takes pleasure in presenting the Distinguished Service Cross to Captain (Field Artillery) Edward Hale Brooks (ASN: 0-6657), United States Army, for extraordinary heroism in action while serving with 76th Field Artillery, 3d Division, A.E.F., at Montfaucon, France, 5 October 1918.

Upon graduation in June 1922 he remained as an instructor in gunnery until November 1926, when he was assigned to the command of Battery 'D' of the 24th Field Artillery Regiment, a pack mule outfit at Fort Stotsenburg, in the Philippines.

From 1932 to 1934 Brooks attended the U.S. Army Command and General Staff School at Fort Leavenworth, Kansas, then went to Harvard University as a Reserve Officers' Training Corps (ROTC) instructor in 1934.

[8] In September 1941, Major General Jacob L. Devers requested that Brooks be named to the staff of the new armored force being formed at Fort Knox, Kentucky.

[8] In this capacity he played a major role in the development of the M-7 self-propelled artillery piece and the howitzer motor carriage M8, both potent forces in armored tactics.

[6] From August 1942 until March 1944 Brooks served as the first commander of the 11th Armored Division[9] at Fort Knox, Kentucky, preparing them for the impending invasion of continental Europe.

Their objective was to assess Allied and Axis strengths and weaknesses and to gather ideas for making armor training more realistic, reflecting actual combat experience.

[4] Major General Brooks assumed command of the 2nd Armored Division on March 17, 1944, at Tidworth Camp, near Salisbury, England.

After a training and preparation period the division embarked from England in LCI's and LST's on June 8, 1944, and stood toward the shores of France.

The problem was solved by mounting huge bulldozer blades on the tanks so that a path could be cut through the natural earthen breastworks for the infantry to follow.

Then came Saint-Lô, the breakthrough at Avranches, where the 2nd Armored Division held the eastern flank, and a series of engagements throughout Northern France and Belgium.

Brooks was cited for gallantry in action during the period August 2 to 6 for making repeated visits to forward elements of his command.

Exposing himself to hostile observation and fire, he expedited the commitment of the division and personally assisted in the organization of continuing attacks by subordinate units in assault on enemy strong points.

[4]: 67  An incident during the drive into Belgium occurred when a corps staff officer came to Brooks' 2nd Armored command post and told the general that he had a mission for the division that he feared was impossible—to be in Ghent in two days.

From training in England, through the Normandy landings, the hedgerow fighting, the breakthrough and the race northeastward across France, through Belgium to the Albert Canal, Brooks had guided the division through two campaigns and scores of operations.

At Marchiennes, France near the Belgian border on September 2, 1944, he himself had personally participated in and directed an operation which annihilated a German convoy of 165 vehicles and earned him an oak leaf cluster to his Silver Star.

For his performance in command of the VI Corps, from December 5, 1944, to March 1945, Brooks was awarded an oak-leaf cluster to the Army Distinguished Service Medal.

[4]: 69  While VI Corps was criticized for exposing its armored forces in towns, Devers noted that "Ted Brooks has fought one of the great defensive battles of all time with very little.

Turning south and crossing the Danube, the corps drove on to the Italian border to meet the U.S. Fifth Army via Brenner Pass.

On May 5, 1945 (two days before Victory in Europe Day) Brooks accepted the surrender of the German 19th Army and 24th Army from General der Panzertruppe Erich Brandenberger in Innsbruck, Austria, thus terminating hostilities in his sector more than 24 hours before the general surrender in Germany and the end of World War II in Europe.

On 24 July 1948, he was awarded the Chilean Grand Cross of the Star of Military Merit, 1st Class, for his long service in their national defense.

[4]: 71 Later in 1948 Brooks was named Assistant Chief of Staff for Personnel (G-1) of the Army and in March 1949 promoted to the three-star rank of lieutenant general.

A great soldier, a keen strategist, and a thoroughly capable administrator, Ted Brooks has all the qualities that would make him an excellent Chief of Staff of the Army.

Eulogizing Brooks, General Charles D. Palmer said: "He was an exceptional and courageous leader who inspired confidence, demanded much of his subordinates but gave more of himself, was very strict but fair, never sought personal power and glory.