- This character is a member of the Kirk family.
His paternal grandfather was Samuel Abraham Kirk, who served as the ship's historian aboard the USS Pioneer, one of the first Federation Starfleet vessels, in the 2160s decade. James Kirk's paternal grandmother is Valeria Williams, who served under Captain Malcolm Reed's command on the Pioneer as armory officer. (ENT - Rise of the Federation novel: A Choice of Futures)
- In Star Trek Generations, in his Nexus experience James T. Kirk finds himself at "his uncle's farm in Idaho", where he met Antonia while riding. It is unspecified whether that uncle was James Kirk, or if it was a brother of his mother.