Commander Kenner was a Starfleet officer serving aboard the ISS Enterprise in the 23rd century.
Kenner had expressed an interest in Lieutenant Marlena Moreau, who was the captain's woman at the time. In 2267, unaware that her captain, James Kirk had been replaced by his parallel universe-counterpart, Moreau threatened to leave him for Kenner, although Kirk dissuaded her from this action. (TOS: "Mirror, Mirror")
This character was only mentioned in dialogue.