He was a professor before his expedition to Exo III. He taught that "freedom of movement and choice produced the Human spirit". He became romantically involved with one of his students, Christine Chapel, who became his fiancée.
In or shortly before 2261, Korby led an expedition to Exo III, where he was badly injured by exposure to the planet's bitter cold. He lived long enough to discover an ancient android civilization there. Using their techniques, he constructed an android body into which he transferred his consciousness. His ruined corporeal form expired that year, but his consciousness survived for over five years as an android. Although he claimed to be the same as an android as he had been as a man, there is evidence that this was not the case; his fiancée, Christine Chapel, was appalled by his callous disregard for the lives of others, and by his plans to selectively introduce android replicas into Federation society. In 2266, his android body was destroyed, leaving open the question of when he had actually died. (TOS: "What Are Little Girls Made Of?")