Stewart enjoyed his new life in Blackfoot, a place that allowed him to ride horses, hunt, take nature walks with his dog, and play basketball. He was well liked in school, where he studied hard and became his class valedictorian when he graduated from Blackfoot High in 1911.
Hoover applied for the United States Military Academy at West Point, New York, was accepted, and began his studies there in 1913. At the Academy he was among many serious students and kept himself in the background for the most part. One exception was when he saved a child from drowning in nearby Lusk Reservoir. Stewart Hoover graduated in 1917 as a second lieutenant and was quickly promoted to first lieutenant.
By June 29, Hoover was in France. He was named a temporary captain of infantry on August 5, 1917.
In the spring of 1918, his family received a dreadful announcement, which began, “I have the honor to inform you that Captain Stewart W. Hoover of Company "I", Eighteenth Infantry, was killed in battle on March 1st. There is no officer in this regiment who has had a better record for gallantry than Captain Hoover and he was killed at the head of his company during a desperate encounter with German storm troops.”
Hoover met his end when a German shell exploded near where he was standing with a gun leveled at the enemy. He was the first soldier from Idaho to die in World War I, and the first West Point officer to die in that gruesome war.
Two American Legion posts are today named in his honor, one at West Point and the other in Blackfoot.