Dr. Leonard H. McCoy is the Chief Medical Officer aboard the Original Starship Enterprise under the command of Captain James T. Kirk. As of 2267, McCoy had earned the Legion of Honor and had been decorated by Starfleet surgeons. Early in his medical career, his father was struck with a terrible, fatal illness. Faced with the prospect of suffering a terrible, lingering death, McCoy mercifully pulled the plug on his father allowing him to die quickly. To McCoy's anguish, a cure for the disease was found a short time after and he carried the guilt of his father's death for many years.
McCoy first joined the Enterprise Crew in 2266, and
remained associated with it and it's predecessor for 27 years afterward.
In 2267, McCoy suffered a serious overdose of cordrazine in a shipboard
accident. In the paranoid delusions that followed, McCoy fled the
ship and went through the Gardian of Forever, a time portal being studied
by enterprise personnel. In the past, he caused serious damage to
the flow of time until Kirk and Spock followed him and restored the original
timeline
In 2268, McCoy was diagnosed with terminal xenopolycythemia
and chose to resign from Starfleet so that he could marry a woman named
natira, High Priestess of the Yonadan people. McCoy rejoined Starfleet
after a cure was found in the Yonadan memory banks.
McCoy retired from Starfleet after the return of
the Enterprise from the five year mission, but he returned to Starfleet
at Kirk's request when the ship intercepted the V'Ger entity near Earth.
McCoy, along with Kirk, was wrongly convicted for the murder of Chancellor
Gorkon in 2293, a conciction that was later overturned. McCoy was
scheduled to retire shortly after the Khitomer Peace Conference, but he
either changed his mind or later returned to Starfleet. As a retired
Starfleet admiral, McCoy made an inspection tour of the Enterprise-D in
2364 at the age of 137.
