John T . Thompson John Taliaferro ( pronounced " tolliver " ) Thompson , ( December 31 , 1860 - June 21 , 1940 ) , was a United States Army officer best remembered as the inventor of the Thompson submachine gun . Early life . Born on December 31 , 1860 in Newport , Kentucky , Thompson grew up on a succession of Army posts and had decided on the military as a career by the age of sixteen . After a year at Indiana University in 1877 , he gained an appointment to the United States Military Academy , graduating in 1882 . His first duty station was in his birthplace of Newport , assigned to the 2nd Artillery as a second lieutenant . He then attended engineering and artillery schools , and was finally assigned to the Army ' s Ordnance Department in 1890 , where he was to spend the rest of his military career . During this period he began his specialization in small arms . Spanish – American War . With the beginning of the Spanish – American War , Thompson was promoted to lieutenant colonel and sent to Tampa , Florida as Chief Ordnance Officer under the top commander for the Cuban campaign , General William R . Shafter . While the rest of the Army was plagued with logistical problems , Thompson on the contrary ran ordnance supply operations to Cuba in a highly efficient manner . Over 18 , 000 tons of munitions were transferred to the battlefield from his Tampa command without any accidents . Thompson was promoted to colonel , the youngest such in the Army at the time . It was also this war which offered Thompson his first exposure to automatic weapons . At the request of Lt . John H . Parker , Thompson arranged for the informal formation of a Gatling gun unit , with fifteen weapons and a generous supply of ammunition , all shipped to Cuba on Thompson ' s sole authority . This unit would later play a significant role in the Battle of San Juan Hill . After the war Thompson was appointed chief of the Small Arms Division for the Ordnance Department . While in this position he supervised development of the M1903 Springfield rifle and chaired the ordnance board that approved the M1911 pistol . For the latter he devised unusual tests involving firing the weapon at donated human cadavers and live cattle to assess ammunition effectiveness . World War I . World War I began in Europe in 1914 , and Thompson was sympathetic to the Allied cause . Since the U . S . did not immediately enter the war , and because he recognized a significant need for small arms in Europe ( as well as an opportunity to make a substantial profit ) , Thompson retired from the Army in November of that year and took a job as Chief Engineer of the Remington Arms Company . While with the company he supervised the construction of the Eddystone Plant in Chester , Pennsylvania , at that time the largest small arms plant in the world . It manufactured 1914 Pattern Enfield rifles for British forces , and Mosin - Nagant rifles for Russia . The introduction of trench warfare in the First World War changed tactics substantially , and by 1916 Thompson was experimenting again with automatic small arms , this time with an eye towards designing a weapon which troops could use to clear an enemy trench — what he called a " trench broom . " Thompson studied several designs and was impressed with a delayed - blowback breech system designed by John Blish , a commander in the United States Navy . With Blish as a partner , Thompson obtained the necessary venture capital to form the Auto - Ordnance Company , and set to work fine - tuning what would eventually become the Thompson submachine gun . When the United States finally entered the war in 1917 , Thompson returned to the Army and was promoted to the rank of brigadier general . He served as Director of Arsenals throughout the remainder of the war , in which capacity he supervised all small - arms production for the Army . For this service he was awarded the Distinguished Service Medal . He retired again after the war , in December 1918 , and went back to work perfecting the " Tommy Gun . " Thompson originally pursued the Autorifle concept : a rifle utilizing the Blish principle delayed - blowback action to avoid the complexity of recoil - operated and gas - operated actions . Testing found that the military issue . 30 - 06 cartridge was too powerful to work satisfactorily using the Blish system . Thompson eventually decided to use the same . 45 caliber ammunition in the Thompson submachine gun that he had vetted for use in the M1911 while in the Army . The weapon was patented in 1920 , but the major source for contracts had dried up with the armistice . Thompson therefore marketed the weapon to civilian law enforcement agencies , who bought it in respectable quantities . However , by 1928 low sales had led the company to financial crisis , and Thompson was replaced as head of the Auto - Ordnance Company . Death . Thompson died at the age of 79 on June 21 , 1940 and is buried on the grounds of the United States Military Academy in West Point , New York . Shortly after his death , the brink of U . S . entry into World War II prompted the Army to order the Thompson submachine gun in large quantities , and it was used extensively during that conflict .