Kyle was a Terran who served as transporter chief under James T. Kirk aboard the ISS Enterprise.
In 2267, Kyle allowed the power beam to wobble during a transport in an ion storm. As a result of this, Spock punished him with his agonizer. (TOS: "Mirror, Mirror")
Like the Kyle in our universe, mirror Kyle was played by John Winston.
The story "The Sorrows of Empire" in Glass Empires gives his name as "Winston Kyle".