In the period immediately preceding World War I, he served at Camp Harry J. Jones, Arizona as his regiment patrolled the U.S. border with Mexico during the Pancho Villa Expedition.

During the First World War, Miles commanded the 371st Infantry Regiment, a unit of the African-American 93rd Division, which he led during combat in France.

In retirement, Miles lived in Staunton, Virginia, where he authored a memoir and participated in numerous civilian activities that supported the U.S. effort in World War II.

[3] Among his classmates who later attained general officer rank were Casper H. Conrad Jr., Adrian Sebastian Fleming, and Thomas Walter Darrah.

[3] From 1900 to 1901, he performed quartermaster duties aboard the Army Transport Service troop carriers Warren and Sheridan, and made numerous month-long trips between Manila and San Francisco.

[5] In May 1916, Miles rejoined his regiment at Camp Harry J. Jones, Arizona as it patrolled the U.S. border with Mexico during the Pancho Villa Expedition.

[7] From January to May 1917, he performed temporary duty with the Department of the Lakes in Chicago as inspector of National Guard units and armories in several midwestern states.

[7] With the army expanding for World War I, in August 1917, Miles was promoted to temporary colonel and assigned to Camp Jackson, South Carolina as commander of the 371st Infantry Regiment, a unit of the African-American 93rd Division.

[7] In August 1919, he became a student at the United States Army Command and General Staff College, from which he graduated in June 1920.

[7][8] In July 1920, Miles was promoted to permanent colonel, and in August he began attendance at the United States Army War College.

[8] In August 1928, Miles was assigned to the University of California, Los Angeles as professor of military science and tactics.

[9] In 1932, he was promoted to brigadier general and assigned to command the 16th Infantry Brigade (now the United States Army Military District of Washington).

[12] 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 First Lieutenant (Infantry) Perry Lester Miles, United States Army, for extraordinary heroism while serving with 14th Infantry, in action near Manila, Philippine Islands, 5 February 1899.

14 and adjacent trenches strongly held by insurgent forces, when the commanding officer was mortally wounded, the advance was checked and the troops were partially demoralized in the face of a heavy concentrated fire from the front and both flanks, Lieutenant Miles assumed command, ordered the advance to continue, and went along the line with utter disregard of the hostile fire and urged his men forward.

Then, with exceptional gallantry and the highest qualities of leadership, he dashed forward, many yards ahead of his men, calling on them to follow, and drove the enemy from their position.

His splendid example of personal heroism, courage, and coolness furnished the needed inspiration to the wavering command and resulted in the successful accomplishment of a seemingly impossible attack.