Remington hailed from Verinus Four, a world that was set aside as a nature reserve, and thus had some experience in dealing with wildlife. During his first landing party, he accompanied his captain, James T. Kirk, to the surface of a world during a survey, in order to determine if the native species of felinoids possessed their own language, and thus should be protected by the Prime Directive and allowed to develop undisturbed.
At one of the creatures' lairs, as he was attempting to gain further sound samples while they were eating, Captain Kirk urged Remington forward, but Remington refused, and indicated that Kirk should move instead. Angered at what he thought was insubordination, Kirk suddenly realized he was standing between a cub and its mother - the only one of the creatures not eating. The mother pounced Kirk, knocking his phaser away and clawing his chest and shoulder. Though under orders not to kill any of the creatures, Remington tried to save his captain by firing his phaser on stun, only to find that the phaser stun did not effect the creatures' nervous system. Yelling to gain the mother's attention, Remington grabbed the cub and tossed it at its mother to distract it, so the science teams could employ shock nets to incapacitate the creature long enough for the landing party to return to the ship. Upon the successful conclusion of the survey, Remington received a commendation for his actions from Captain Kirk.
During a battle against a Klingon battlecruiser, Remington was manning Auxiliary Control when a freak burst of energy from the Klingon attack short-circuited his involuntary nervous system, leaving him essentially trapped deep within his own mind. Chief Medical Officer Leonard McCoy was able to stabilize him physically, but the kind of nerve damage he had sustained could not be repaired. However, First Officer Spock revealed that he had learned of an experimental nerve regeneration technique developed by Dr. Daniel Corrigan and the healer Sorel, the esteemed medical team at the Vulcan Academy of Sciences; his mother, Amanda Grayson, had been diagnosed with degenerative xenosis and was undergoing the treatment herself. Dr. McCoy arranged with Dr. Corrigan and Sorel to have Remington undergo the regeneration therapy, along with Amanda and Sorel's wife T'Zan, who had suffered an accident involving equipment in her lab.
After T'Zan was killed by what seemed to be an equipment failure, extra security was placed around the stasis chambers, but to no avail; Remington's was the next stasis chamber to fail, and he died instantly. Remington's death led Captain Kirk to suspect murder, leading him to a deranged assistant of Ambassador Sarek, who had attempted to kill Amanda so she could marry Sarek; T'Zan and Remington had been "collateral damage". During his murder investigation, Kirk composed a letter of condolence to Remington's family, officially stating that he had died as a result of wounds incurred in battle with the Klingons, in defense of the Federation. (TOS novel: The Vulcan Academy Murders)