James Tiberius Kirk was born in Iowa,Earth in 2233. When Kirk was 13 he was one of the nine who was a living eyewitness to the massacre of 4,000 colonists on Tarsus IV by Conos the Executioner(The Conscience of the King[TOS]).
Kirk entered Stafleet Academy at the age of 17 and was noted for the only cadet to defeat to defeat the no win Kobayashi Maru scenario. He did this by reprogramming the simulation and was commended for original thinking.
After Starfleet Academy his first assignment was as a lieutenant aboard a the U.S.S. Faragut. While on a mission aboard the ship a landing party including himself went to Tycho IV where 200 crew including the captain were killed by a cloud creature. Although Kirk could have done nothing to stop there deaths he blamed himself for the incident.
In about 2263 Kirk and Dr. Carol Marcus had a son, David Marcus. Kirk was not involved with the raising of his son because David’s mother requested that it be that way. He didn’t have contact with his son until 2285 when David and Carol Marcus were working on the Project Genesis. While there he saved them from Khan Noonien Singh’s wrath. Unfortunately, shortly after that David died at the hands of a klingon who was trying to obtain the secret of Genesis.
In 2264 Kirk became Captain of the U.S.S. Enterprise . His explorations aboard the Enterprise are what made him a Starfleet legend. His crew namely Dr. Leonard McCoy, First Officer Spock, and Montgomery Scott were also legends on the Enterprise. They traveled the galaxy escaping death and learned much about the unknown.
When the ship came back to Starfleet Command from the five-year mission Kirk was promoted to Admiral and was put in charge of Starfleet operations. He accepted a grade reduction when Starfleet needed him to captain a Voyage to take care of the V’ger threat in 2271(during the mission Kirk found out that V’ger as it called itself was actually Voyager VI)(Star Trek: The Motion Picture).
Kirk’s first retirement took place sometime between 2276 and 2282. Kirk came out of retirement at the rank of Admiral to train cadets in Starfleet Academy. He came back into active duty in 2285 when Khan stole the starship Reliant and the Genesis device (Star Trek II: The Wrath of Khan). During the battle Spock died but fortunately McCoy and Spock had mind melded putting Spock’s mind into McCoy. Spock’s body went through space and landed on the Genesis planet where it was regenerated. His body and mind were reunited on the planet Vulcan where Kirk ordered the destruction of the Enterprise to prevent it from falling into Klingon hands (Star Trek III: The Search for Spock). They used a captured Klingon ship to return to Earth to stand trail for 9 Starfleet regulations. On the way an alien probe of unknown origin was interfering with earth’s weather conditions making it unable to safely return. Spock noticed that the transmission the probe was sending (which Starfleet had no way of answering) was that of a humpback whale which had gone extinct. So the crew did a slingshot around the sun which put them into a time warp to the 1980’s when the humpback whale was not extinct. After bringing back the whales to the 23rd century the probe went away returning the weather to it’s normal. For saving the Earth all but one charge was dropped. The remaining charge that of directly disobeying a superior officer demoted him to captain. Once again a captain he took over the newly commissioned Enterprise A (Star Trek IV: The Voyage Home).
Shortly after his second retirement he was a guest of honor on the maiden voyage of the Enterprise B where they believed him killed (2293). He was not dead but swept into a temporal displacement called the Nexus. It was not until 2371 did he return when Captain Jean Luc Picard was also pulled into the Nexus from there the two joined forces to save the people of the Veridian Star system from destruction by the scientist Soran. During that time Kirk was killed. He is buried on a mountaintop on Veridian III.