World War I
When the United States entered World War I in April 1917, D’Olier offered his services to the Quartermaster Corps, believing his experience in the textile industry would prove useful in the war effort.
He was commissioned as a captain and served at the Boston Quartermaster Corps Depot until receiving orders to go to France in August of 1917.
D'Olier was assigned to command the first salvage depot of the American army in France with 12 personnel.
Within six months, his salvage staff grew to 6,000 and served about 750,000 men, making it the largest salvage depot in France
The salvage service saved the American Expeditionary Forces (AEF) millions of dollars and provided work for the war-torn French people.
His work earned D’Olier a promotion to lieutenant colonel, a Distinguished Service Medal and a Chevalier of the Legion of Honor from France.