During World War I he served with the Pancho Villa Expedition in Mexico and the American Expeditionary Force in France in logistical posts.

[3] Somervell was appointed to the United States Military Academy at West Point, New York by Congressman Charles C. Reid of Arkansas.

[7] Somervell returned to Washington Barracks to attend the Engineer School but his course was interrupted by the declaration of war by the United States on Germany on 6 April 1917.

The 15th Engineers worked on several construction projects, including a munitions dump at Mehun-sur-Yèvre and an advanced depot and regulating station at Is-sur-Tille.

[8] For his role, Somervell was awarded the Army Distinguished Service Medal (DSM), the citation for which reads: The President of the United States of America, authorized by Act of Congress, 9 July 1918, takes pleasure in presenting the Army Distinguished Service Medal to Lieutenant Colonel (Corps of Engineers) Brehon Burke Somervell (ASN: 0-3665), 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.

In all these positions Lieutenant Colonel Somervell displayed unusual vision, initiative, sound judgment, and high professional skill, contributing in a conspicuous way to the successful operation of the American forces in France.

[10] For leading a three-man patrol to inspect damage to a bridge some 600 yards (550 m) in front of American lines, Somervell was awarded the Distinguished Service Cross.

[4] The citation for the medal reads: The President of the United States of America, authorized by Act of Congress, 9 July 1918, takes pleasure in presenting the Distinguished Service Cross to Lieutenant Colonel (Corps of Engineers) Brehon Burke Somervell (ASN: 0-3665), United States Army, for extraordinary heroism in action while serving with 89th Division, A.E.F., near Pouilly, France, 5–6 November 1918.

Voluntarily serving on the staff of the 89th Division, Lieutenant Colonel Somervell conducted the first engineering reconnaissance of the damaged bridges at Pouilly, advancing more than 500 meters beyond the American outposts, crossing three branches of the Meuse River, and successfully reconnoitering the enemy.

[9]He was one of only nine American officers, including Douglas MacArthur, Barnwell R. Legge, Sereno E. Brett or William J. Donovan, to have been awarded both the DSC and the Army DSM in the First World War.

The 89th Division returned to the United States in May 1919 but Somervell remained behind as Assistant Chief of Staff, G-4,[nb 1] in charge of supply, of the Third Army, and the American Forces in Germany, as it was re-designated on 2 July 1919.

[12] While in Germany, Somervell also met Walker Hines, a prominent New York corporate lawyer, whom he assisted with a survey of shipping and navigation on the Rhine River.

After graduation he was posted to the 1st New York Engineer District but soon obtained leave to assist Hines with a special study of navigation on the Rhine and Danube Rivers on behalf of the League of Nations, essentially a continuation of the work that the two men had done in 1920.

As such he became involved in a conflict between proponents of the development of hydroelectric power through damming the Great Falls of the Potomac River and the Maryland-National Capital Park and Planning Commission.

[20] Early in his administration he worked to repair relations with labor unions and left-wing groups that had suffered under his strongly anti-Communist predecessor Victor F. Ridder.

He also began a program of censoring the content of WPA-financed murals and other art, giving instructions to “guard against anything in which the main idea is social content, rather than artistic value, and eliminate anything that may savor of propaganda, and to see that the project devotes itself to art and not politics.”[23] In his most controversial decision, in July 1940 he ordered the burning of three out of four murals on the history of aviation at Floyd Bennett Field in Brooklyn because of the inclusion of supposed Communist symbols.

[24][25] In December 1940, Somervell became head of the Construction Division of the Quartermaster Corps, and was promoted to the temporary rank of brigadier general on 29 January 1941.

His immediate concern was the construction of a series of camps—which were scheduled for completion by April 1941—to house the large numbers of draftees who were then entering the Army.

Bergstrom was a former president of the American Institute of Architects;[28] Casey a Corps of Engineers officer seconded to the Construction Division.

[30] Somervell gave them until 9 a.m. on Monday morning to design the building, which he envisaged as a modern, four-story structure with no elevators on the site of the old Washington Hoover Airport.

Over that "very busy weekend", Casey, Bergstrom and their staff roughed out the design for a four-story, five-sided structure with a floor area of 5,100,000 square feet (470,000 m2)—twice that of the Empire State Building.

[32] President Roosevelt subsequently moved the site of the building, over Somervell's objections, in order to prevent it being constructed in front of Arlington National Cemetery.

The outbreak of war led to a new urgency, and by May 1942, some 13,000 workers were working around the clock on the building, which was completed in early 1943 at a cost of $63 million, the overrun being caused by the emphasis on speed and the addition of the extra floor.

Reybold, who considered Somervell "a firecracker but ruthless" who "didn't care who he hit", selected Brigadier General Thomas M. Robins to head the new Corps of Engineers Construction Division.

There was something in the drive of the Commanding General of the A.S.F., his quickness on the mental trigger, his adroitness and his evident ambition to tackle tough jobs that in itself lent some support to this feeling of impending encroachment among those of a more deliberate pace.

[46]A 1943 attempt by Somervell to abolish the Technical Services failed amid the furor and panic created by false rumors that he was being considered for the post of chief of staff if Marshall was sent to Europe to command the Supreme Headquarters Allied Expeditionary Force.

[47] Somervell sometimes pushed extravagant white elephant projects, such as the Canol Road, which he continued long after the strategic imperative behind it had faded.

[12] Somervell accepted an offer to become president of Koppers, a Pittsburgh-based company that mined coal and manufactured and sold coal-based products.

[1] The USAT General Brehon B. Somervell, a US Army Logistics Support Vessel based in Yokohama, Japan that can carry up to 2,000 short tons (1,800 t) of cargo, is named in his honor.