James T. Kirk's older brother, a life sciences officer and xenoanthropologist aboard Pike's Enterprise.
George Samuel Kirk Jr., known as Sam, is a life sciences officer aboard the USS Enterprise under Christopher Pike and the older brother of James T. Kirk. He is played by Dan Jeannotte, who wears a mustache in a nod to the brief appearance of a dead Sam Kirk, played by William Shatner, in the original series.
Sam and Jim have a complicated relationship shaped by their different personalities. When the Gorn attacked the colony Parnassus Beta, Sam joined Pike's secret landing party and was captured along with La'An Noonien-Singh, Joseph M'Benga, Erica Ortegas and many colonists.
The group escaped from the Gorn with transporter codes that let the Enterprise rescue the colonists. Later, Sam was among the hostages taken by Dana Gamble after a Vezda possessed the junior medical officer.