commanding officer; commander; commandant
A military officer in command of a unit, installation, or operation. Can refer to ranks from general to captain depending on context.
The commanding officer ordered the troops to withdraw.
彼は海軍の司令官に任命された。
He was appointed commander of the naval forces.
He was appointed commander of the fleet.
The soldiers acted according to the commander's orders.
He served as the base commander for many years.