Miller was living in St. Louis, Missouri when he made the decision to enlist in the 6th Missouri Infantry Regiment (Missouri National Guard) in 1898, serving with the regiment in Cuba during the Spanish-American War. He later joined the U.S. Army and was awarded the Medal of Honor for bravery while serving with the 6th U.S. Cavalry during the Moro Rebellion (Philippine-American War) in 1909. During World War I, he served with the U.S. Army Air Service. Lt. Col. Miller died in the crash of an Army passenger plane in 1921 and is buried in Arlington National Cemetery.