Captain Kirk was the principal lead character in the original Star Trek series. Shatner voiced Kirk in the animated Star Trek series and appeared in the first seven Star Trek movies. Chris Pine portrayed a younger version of the character in the 2009, 2013, & 2016 Star Trek films, with Jimmy Bennett playing Kirk as a child. Other actors have played the character in fan-created media, and the character has been the subject of multiple spoofs and satires. Kirk also appears in numerous books, comics, and video games. The character has been praised for his leadership traits, and also criticized for his relationships with women. His middle name was not disclosed during the original series or movies.
In the TBBT gang, Sheldon considers Leonard to be the Kirk in their landing party. He considers himself to be Spock.
In "The Adhesive Duck Deficiency", the geo-location for their desert viewing of the meteor shower was given by Raj: 34.48 N, 118.31 W placing them within the Vasquez Rocks Park; the location of several Star Trek episodes including the one where Captain Kirk rolls a rock on to the reptilian Gorn which also makes appearances in two of Sheldon's dreams.
In "The Apology Insufficiency", Sheldon toasts Captain Kirk upon his solution for the "Kobayashi Maru" simulation. Kirk reprogrammed the simulator and Sheldon attempts to reprogram Howard to apologize to him.
In "The Staircase Implementation", Sheldon meets Leonard and asks him "Kirk or Picard?" to determine whether his sci-fi opinions are "correct". After thinking, Leonard replies that he prefers the original series to The Next Generation, but Picard over Kirk, which is the answer Sheldon was looking for.
In "The Agreement Dissection", Sheldon uses a self-destruct sequence on his laptop, akin to when Captain Kirk in "Let That Be Your Last Battlefield" threatened to blow up the Enterprise.
In "The Nerdvana Annihilation", per the Star Trek series, Captain Kirk steals the cloaking device on 5027.3, which converts to January 10, 2328. (This refers to the Star Trek episode "The Enterprise Incident", which was actually set in late 2268.).
In "The Creepy Candy Coating Corollary", Sheldon yells "Wheaton" like Kirk yelled "Khan" in Star Trek II.
In "The Egg Salad Equivalency", Leonard became extremely happy for various reasons, one of which was when he took an online quiz called "Which Star Trek character are you?" and he got Captain Kirk after 4 tries. Later, he admitted to Penny that he really does feel like Captain Kirk after having so many women show interest in him; Penny then tells him that this will stop if he keeps mentioning Captain Kirk, causing him to say "Message received" a la Shatner.second season, she is labeled as their McCoy.