While he was still a cadet, Bloch served aboard battleship USS Iowa during the battle of Santiago de Cuba.

Bloch assisted in the rescue of Spanish sailors from the burning enemy ships and was subsequently awarded with the Specially Meritorious Service Medal.

Following this assignment, he reverted to his permanent grade, rear admiral, and commanded the Fourteenth Naval District at Pearl Harbor at the time of the attack.

Shortly before the attack, he and Admiral Husband E. Kimmel discussed the possibly sighting and sinking of a submarine by the USS Ward.

He remained as chairman of the Navy Board for productions awards until the end of World War II and retired in 1946.