Tommy Carter was a Human man, a Starfleet officer assigned to the operations division of the Federation starship USS Enterprise under the command of Captain James T. Kirk in the 2260s.
While Tommy Carter was at Starfleet Academy, he met and fell in love with Leon Sawchuk. They maintained a steady relationship, and eventually both served together aboard the Enterprise.
In 2269 or 2270, Carter drowned in a corridor when the Enterprise was flooded by Ulum near Polymax VIII. Sawchuk was grief-stricken. James T. Kirk consoled him, knowing that the two had been together for a long time. (TOS comic: "What Pain It Is to Drown")