The first atomic bomb, "Little Boy," was dropped from a B-29 bomber named the Enola Gay, which was piloted by U.S. Army Air Force Colonel Paul Tibbets, Jr.
While the question asks "who shot," it's important to clarify that an atomic bomb is not fired in the traditional sense. It's a gravity bomb, meaning it's dropped from an aircraft. Therefore, Colonel Paul Tibbets, Jr., as the pilot in command of the Enola Gay, was responsible for delivering and releasing the bomb over Hiroshima on August 6, 1945.
Therefore, Colonel Paul Tibbets, Jr. can be considered the person who "shot" or, more accurately, dropped the first atomic bomb.
