Like most of the crew of the original USS Enterprise, Spock has become something of a legend in Starfleet history. He was the first Vulcan ever to serve in Starfleet, joining the Academy in 22491 at the age of nineteen.2 In his final year he served on board the USS Enterprise;3 he participated in that ships mission to Talos IV which resulted in the planet being placed under quarantine.4
After graduation Spock continued to serve on board the Enterprise. His time on the vessel totalled some thirty two years, longer than any other officer in the ship's history - indeed, apart from a short retirement to undergo the Kolinahr discipline on Vulcan5 and a few months spent on the same planet after his death,6 Spock served on the Enterprise continually throughout his entire Starfleet career.
Although Spock sought command in his early career7, he later came to dislike the idea of his own captaincy. Nevertheless, he became captain of the Enterprise for training duties only while at the Academy. When the Genesis crisis arose in 2285 Spock turned command over to Admiral Kirk; during this crisis Spock entered an engineering compartment which had become heavily contaminated with radiation in order to make repairs to the main energiser. Spock died shortly afterwards from radiation poisoning and was buried on the Genesis planet.5
Unknown to the crew of the Enterprise at the time, Spock had used a Vulcan mind meld to transfer a copy of his consciousness to Dr McCoy. David Marcus subsequently discovered that the Genesis effect had regenerated Spock's body, and Admiral Kirk took this body to Vulcan to allow Spocks mind to be rejoined with his body in the fal-tor-pan ceremony on Mount Seleya. This was a success, and Spock lived again.8
Spock subsequently participated in Admiral Kirk's journey to 20th Century Earth to pick up a pair of humpbacked whales. Once the Enterprise crew returned to Starfleet he was appointed as science and executive officer of the Enterprise-A,6 a post which he continued to fill for a further eight years. In 2293 Spock's father, Sarek, made peace overtures to the Klingon Empire after the Praxis disaster. Spock volunteered the Enterprise to take part in the talks; when the Klingon Chancellor was assassinated by two Enterprise crewmembers, Spock uncovered a conspiracy of Starfleet and Klingon personnel to sabotage the peace conference. Spock rescued Kirk from the surface of the Rura Pente asteroid in time to go to Khitomer and save the peace conference.9
After his eventual retirement from Starfleet, Spock became a Federation ambassador. In 2368 it was feared that he had defected to Romulus,10 but in fact he was working undercover on that planet in order to promote reunification between the Vulcans and Romulans.11 He remains there at present.