- See Harper for other articles with titles that contain, either by relationship or by coincidence, this character's surname.
In 2268, Harper participated in the repair of the starship's warp-propulsion systems when the Enterprise encountered a swarm of ancient mechanized, telepathic bioships destroying local stars for sustenance. (TOS - New Visions comic: "Swarm")
When the Enterprise was assigned to test the M-5 computer later that same year, Harper was one of the crewmembers left aboard as part of the skeleton crew. Unfortunately, Harper died shortly after when he attempted to disconnect the computer from the Enterprise's power systems, and M-5 increased the flow and vaporized him. (TOS episode & Star Trek 9 novelization: The Ultimate Computer)
- TOS - New Visions comic: "More of the Serpent Than the Dove"
- TOS - New Visions comic: "Swarm"
- TOS episode & Star Trek 9 novelization: The Ultimate Computer