Dr. McCoy, or 'Bones' as he was affectionately known by his friends, was famous for his on-screen arguments with the ever logical Spock.
McCoy was almost everything that Spock was not.. He constantly ostracised Spock for his lack of feeling, or emotion for the plight of others. As most fans will know, this was not strictly true, and despite all this, it was obvious that a bond of friendship existed between the two (this was later to be proved just before Spock's death in 2285, when Spock mind melded with McCoy and entrusted his katra to the doctor).

McCoy attended the University of Mississippi, around 2245. It was at this time hat he had a romance with Emony Dax while she was visiting Earth to judge a gymnastics competition.

For many years, McCoy carried with him, the guilt of the possibly needless death of his father. Early in his medical career, his father was struck with a terrible, fatal illness. Unable to face the prospect of his father suffering a long and painful disease, McCoy 'pulled the plug' on him, allowing him to die.
Although this was a mercy killing, to his great anguish, a cure was found for the disease shortly after his fathers death.

McCoy first joined the Enterprise in 2266 and remained with the ship, and its successors, for 27 years.

Suffering from a cordrazine overdose, the result of a shipboard accident, McCoy jumped through a time portal, that was under investigation by the crew, and seriously affected the flow of time until Kirk and Spock followed him and restored the shape of history.

In 2268, McCoy retired from Starfleet after being diagnosed with the terminal illness Xenopolycythemia. This was so that he could marry a Yonadan high priestess, Natira. He returned to Starfleet when a cure for the disease was discovered in the Yonadan memory banks.

He again retired after the end of the five year mission, but returned , at the request of Kirk, when the V'ger entity was intercepted near Earth.

McCoy and Kirk were wrongly accused and convicted for the murder of the Klingon Chancellor Gorkon in 2293. The conviction was later overturned.

Finally, as a retired Starfleet admiral, McCoy made an inspection tour of the Enterprise - D, under the command of Jean-Luc Picard, in 2364 at the age of 137.