Leonard H. McCoy.

Based on McCoy's age of 137 in "Encounter at Farpoint" (TNG), (2364), we believe the good doctor was born in 2227. A large number of uncertainties exist regarding McCoy's early years, prior to his service aboard the first Starship Enterprise. We conjecture that he entered college or medical school in 2245 (assuming he was 18 at the time) and that he graduated in 2253 (assuming an eight-year medical program). Significant questions remain, however, as to whether or not those years were spent at Starfleet Academy or if he attended another school.

The main uncertainty surrounds a back story developed for McCoy by Dorothy Fontana and Gene Roddenberry in which McCoy had married, but that marriage ended in a bitter divorce. In this scenario, the emotional aftermath of this divorce was what drove McCoy to abandon a private medical practice and join Starfleet. This back story would have been described in an episode written by Fontana called "Joanna," which would have shown McCoy's grown daughter coming on board the Enterprise. (The episode was never produced, and was extensively rewritten, eventually becoming 'The Way to Eden" [TOS].) Because none of this material was ever incorporated into any aired episodes, we have not included it in the main body of this chronology. We mention it here because it offers some fascinating insight into the McCoy character, and because it does not significantly conflict with any aired material.

McCoy's father: Star Trek V The Final Frontier established that sometime after McCoy had earned his medical degree, his father, David (name established in Star Trek III: The Search for Spock), suffered from a terminal disease that caused the elder McCoy terrible pain Leonard "pulled the plug" on his father out of compassion, but was horrified when, shortly thereafter, a cure was discovered for the affliction.

McCoy had been briefly stationed on planet Capella IV apparently as part of a Starfleet mission sometime prior to his assignment to the Enterprise (2265). McCoy would later recall that the Capellans were totally uninterested in medical aid or hospitals because of a cultural belief that only the strong should survive ("Friday's Child" [TOS]). Sometime prior to "Court Martial" (TOS), (set in 2267), McCoy had earned the Legion of Honor and had been decorated by Starfleet surgeons.

Dr. McCoy lived at least until the first season of Star Trek The Next Generation (2364), since he made an inspection tour of the Enterprise D in "Encounter at Farpoint" (TNG) the age of 137.

2227: Born ("Encounter at Farpoint" FNG]).

2245: Enters medical school (conjecture).

2253: Graduates medical school (conjecture).

2266: Assigned to U.S.S. Enterprise (conjecture).

2270: Retires from Starfleet (Star Trek: The Motion Picture).

2271: Returns to Starfleet (Star Trek: The Motion Picture).

2364: Conducts inspection tour of Enterprise-D at age 137 ("Encounter at Farpoint" [TNG]).