On April 23, 1890, he was awarded the Silver Lifesaving Medal for rescuing a sailor from drowning in the Narrows off Governors Island in New York City on July 27, 1889.

[1] Although his father and grandfather were alumni of the Military Academy, Frank Tompkins eschewed an appointment himself and entered the Army directly from civilian life, commissioned a second lieutenant in the 8th Cavalry on August 1, 1891.

His unit engaged in counter-guerrilla operations against General Miguel Malvar and his 3,000 insurrectos during the successful final campaign of the Philippine–American War between December 1, 1901, and April 30, 1902.

On March 9, 1916, Tompkins, now a major, commanded the 3rd Squadron of the 13th Cavalry at Columbus, New Mexico and was acting as regimental executive officer when it was attacked by revolutionary forces under Pancho Villa.

During the Punitive Expedition that ensued, Tompkins led several provisional squadrons in "flying columns" deep into Mexico in search of Villa.

Before this took place, however, he was promoted to colonel in June and his orders changed to take command of the 301st Infantry Regiment ("Boston's Own"), 76th Division, being formed for training at Camp Devens, Massachusetts.

He reported August 12 and led the 110th during the Oise-Aisne Campaign until September 7, when he was severely wounded and temporarily blinded at Baslieux-lès-Fismes in a mustard gas attack.

Tompkins returned to the United States in December 1918, stationed at Fort Myer, Virginia, until March 1919, when he again became a professor and commandant of cadets at Norwich.

His father, Charles Henry Tompkins, received the Medal of Honor for leading his troop of the U.S. 5th Cavalry in a mounted charge at the Battle of Fairfax Court House during the American Civil War, and was brevetted a brigadier general.

The Distinguished Service Cross is presented to Frank Tompkins, Major, U.S. Army, for extraordinary heroism in action at Columbus, New Mexico, March 9, 1916.