Lieutenant Osborne was a male Human Starfleet officer in the 23rd century. He served aboard the USS Enterprise in 2267 under the command of Captain James T. Kirk, during the historic five-year mission.
That same year, on stardate 3192, he accompanied Captain Kirk in the landing party that visited Eminiar VII. Briefly imprisoned, the landing party escaped custody, and Osborne impersonated an Eminian guard to assist Spock in rescuing Ambassador Robert Fox from the Eminian authorities' attempt to execute him. He was also present when Spock stormed the High Council chamber, thinking to rescue Kirk, who as it turned out did not need that kind of help. Osborne assisted Fox in guiding the High Council out of its chambers so that none of them would be injured when Kirk destroyed the war-fighting computers. (TOS: "A Taste of Armageddon")
Later that year, on stardate 3196, Osborne was part of Lieutenant Commander Giotto's team on Janus VI that hunted for the mother Horta who was killing miners on the planet. (TOS: "The Devil in the Dark")