Lieutenant Harrison was a male Human Starfleet officer who lived during the mid-23rd century. He served aboard the USS Enterprise under Captain James T. Kirk, from 2266 to 2269, during a historic five-year mission that starship undertook. In 2267, he was originally a technician first class and later a lieutenant.
In 2266, Harrison served in the sciences division, and sat at a forward bridge station during a star mapping mission that led to a tense first contact with the First Federation starship Fesarius on stardate 1514.0. Harrison was one of many bridge officers who were violently ejected from their seats when the Enterprise was forced to destroy a radiation-emitting space buoy operated by Balok. (TOS: "The Corbomite Maneuver")
Harrison was working in the ship's biopsy lab in 2266 when Enterprise personnel were afflicted with an intoxication from Psi 2000. Upon McCoy requesting a report from Harrison, a specific crewman began laughing hysterically over the speaker. Harrison was later at his post in sickbay (wearing a sciences blue jumpsuit uniform), helping to restrain Hikaru Sulu, while McCoy tested antidote serums. (TOS: "The Naked Time")
Later that year, Harrison (again wearing a sciences blue jumpsuit uniform) was working in a corridor adjacent to Charles Evans' quarters, at a panel labeled "atmospheric system". Harrison carried out this work while Spock was standing beside him and was meanwhile aware that Spock intended to use a force field. After Spock stated he would activate the force field himself and that Harrison had permission to return to his duties, Harrison did so. (TOS: "Charlie X")
Harrison was part of a security team that responded to a call of trouble at the ship's theater. Lenore Karidian stole Harrison's phaser to hold Enterprise crewpeople at bay. She accidentally discharged the weapon and killed her father, Kodos. (TOS: "The Conscience of the King")
When Khan Noonien Singh attempted to take over the ship in 2267, Harrison was wearing a red operations division uniform while among multiple crewmembers who were trapped, by Khan, on the bridge. Kirk's captain's log noted commendations for numerous personnel, including Technician First Class Harrison, who lost consciousness from oxygen deprivation. (TOS: "Space Seed")
Lieutenant Harrison, wearing a gold command division uniform, was among Starfleet personnel that beamed down to Omicron Ceti III in 2267. When sub-sonic vibrations were used to irritate Omicron spore-possessed crewmembers on that planet, Harrison was overcome by the effect and started fighting with Lieutenant Kelowitz and another crewmember. (TOS: "This Side of Paradise")
- "The Corbomite Maneuver"
- "Mudd's Women"
- "The Man Trap"
- "The Naked Time"
- "Charlie X"
- "Balance of Terror"
- "The Conscience of the King"
- "The Galileo Seven"
- "The Menagerie, Part I" (stock footage only)
- "The Menagerie, Part II"
- "Shore Leave"
- "The Alternative Factor"
- "The Return of the Archons"
- "A Taste of Armageddon"
- "Space Seed"
- "This Side of Paradise"
- "The Devil in the Dark"
- "Errand of Mercy"
- "The City on the Edge of Forever" (stock footage only)
- "Operation -- Annihilate!"
- "Metamorphosis" (stock footage only)
- "The Omega Glory" (stock footage only)
- "Assignment: Earth" (stock footage only)
- "Elaan of Troyius" (stock footage only)
- "And the Children Shall Lead" (stock footage only)
- "Spock's Brain" (stock footage only)
- "The Cloud Minders" (stock footage only)
- "Turnabout Intruder" (stock footage only)
The name Harrison was among several others mentioned by Kirk in "Space Seed", but not specifically directed towards any one character, and is based on the timing of the camera's pan across the bridge in association with Kirk's dialogue.
Harrison was one candidate rumored to possibly be an antagonist in the film Star Trek Into Darkness. Before the movie was released, a name for the villain was revealed to be "John Harrison", though whether this was his actual name or merely an alias was undisclosed. Star Trek Magazine issue 172, p. 32, in the lead-up to the film's release, speculated a fifty percent probability that the character would turn out to be Lieutenant Harrison.