Final answer:
Major General Smedley Butler and Lieutenant Thomas Custer are the only two individuals who have received the Medal of Honor twice for their exceptional acts of bravery during the time of the Mexican Revolution and World War I, and the American Civil War, respectively.
Step-by-step explanation:
Only two individuals in the history of the United States military have been awarded the Medal of Honor twice. The first is Major General Smedley Butler, who was a Marine Corps officer during the Mexican Revolution and World War I.
The second is Army Lieutenant Thomas Custer, who served during the American Civil War and is also the younger brother of the famous General George Armstrong Custer.
Major General Butler received his first Medal of Honor for his leadership during the occupation of Veracruz in 1914, and his second for bravery during the Haiti Campaign in 1915.
Lieutenant Thomas Custer was awarded both of his Medals of Honor for separate acts of bravery during the Civil War. Notably, these rare double decorations highlight the exceptional gallantry and heroism displayed by these servicemen in the line of duty.
It is important to mention that while figures like Staff Sergeant Ruben Rivers and Marine Eugene Obregon showed outstanding bravery, resulting in awards such as the Medal of Honor and Presidential citations, they are not double recipients of the Medal of Honor.
Their stories of valor are nonetheless recognized and commemorated with the highest honors.