Mike

From Memory Alpha, the free Star Trek reference.

Mike was a 23rd century Starfleet officer specialized in the command division. He graduated with James T. Kirk from Starfleet Academy and was a mutual friend of Kirk and Ben Finney.

In 2267, while on a layover at Starbase 11, Mike gave Kirk the cold shoulder following the apparent death of Finney, blaming Kirk for killing his friend. He was at the time, sharing a drink at the bar with his friend Timothy. (TOS: "Court Martial")

Although not explicitly stated on screen, Mike may have served aboard the USS Republic along with Kirk and Finney.