Commander of the MACO detachment assigned to Enterprise for the Xindi mission, whose rivalry with Malcolm Reed ended in respect.
Major J. Hayes led the Military Assault Command Operations troops who joined Enterprise in 2153 for its mission into the Delphic Expanse. Played by Steven Culp, he first appeared in The Xindi, and his full first name was never given on screen.
The arrival of a separate military unit created friction with Malcolm Reed, the ship's armory officer and security chief. Their tension came to a head in Harbinger, when Hayes proposed joint training and Reed saw it as a challenge to his authority, and the two came to blows before reaching an understanding.
In Countdown, Hayes led a MACO squad, supported by Reed, to rescue Hoshi Sato from a Xindi-Reptilian ship. With the damaged transporter able to beam out only two at a time, he sent his team out first and was shot by a Reptilian as he beamed away. He died aboard Enterprise after telling Reed who should succeed him.