Toshi Opatashu was a Federation Starfleet line and flag officer on active duty in at least the 23rd century.
Saavik served under Captain Opatashu when the latter was commanding officer of the USS Coral Sea. He had her transferred after she called him "incompetent". (Orion Press: Chekov's Enterprise)
Opatashu later became head of Starfleet Intelligence. (Orion Press: "Before the After")