Logan joined the Texas National Guard from Luling, Texas in 1936, at the age of 15. By September 9, 1943 he was serving as a Sergeant in the 142nd Infantry Regiment, 36th Infantry Division. On that day, he participated in the Allied landings near Salerno, Italy. Logan single-handedly captured a German machine gun emplacement and later killed an enemy sniper. For these actions, he was awarded the Medal of Honor ten months later, on July 5, 1944.