The highest Naval rank in peacetime. (see Fleet Admiral) (background) The Admiral insignia has four silver stars in a row. Prior to the Civil War, Captain was the highest Naval rank When placed in command of larger units, Admirals were sometimes designated a Flag Officer, but that was a billet, not a rank. The current admiral ranks (from junior to most senior) are: Rear Admiral (lower half), one star; Rear Admiral (upper half), two stars; Vice Admiral, three stars; Admiral, four stars and Fleet Admiral, five stars.