J. Hayes was an officer of Earth's Military Assault Command Operations on active duty in the early to mid-22nd century. From 2153 until his death in 2154, Major Hayes was commanding officer of the MACO detachment aboard Enterprise (NX-01). (ENT: "The Xindi", "The Shipment", "Harbinger", "Hatchery", "Countdown") Hayes was critically injured during a mission in which a contingent from Enterprise was exfiltrating Hoshi Sato, who had been abducted by Xindi-Reptilians. He later succumbed to his injuries. ("Countdown")