Lemli served in the operations division aboard the Enterprise, performing the duties of engineer and security officer during the historic five-year mission . By stardate 4729.4, he held the rank of ensign. (TOS: "The Ultimate Computer")
He enjoyed listening to contemporary music of the 2260s, much to the disappointment of Lieutenant Commander Montgomery Scott, the chief engineer. (TOS: "The Way to Eden") During breaks from duty, he socialized with his shipmates in a bar. (TOS: "The Trouble with Tribbles"; DS9: "Trials and Tribble-ations")
On his first assignment, he was posted to the engineering station on the bridge on stardate 3468.1 when the Enterprise was caught and held in a force field by an alien claiming to be the Greek god Apollo. (TOS: "Who Mourns for Adonais?") He assisted Scott in the main engineering room and fixed the warp drive after the space probe Nomad tampered with it on stardate 3541.9. (TOS: "The Changeling") He returned to the engineering station on stardate 4040.7 when the starship orbited the planet 892-IV. (TOS: "Bread and Circuses")
He assisted Lieutenant Kyle in the transporter room on stardate 4202.1 and beamed the damage control party over to the USS Constellation and back during the battle with the "planet killer". (TOS: "The Doomsday Machine") He beamed up the landing party during a medical emergency on stardate 4211.4, after Commander Spock was wounded by gunfire from a hostile tribe on the planet Neural. (TOS: "A Private Little War")
He was assigned to the security team aboard Deep Space Station K-7 on stardate 4523.3. He briefly encountered Cyrano Jones and helped end a bar brawl between the Klingons and the Enterprise crew. Later, he was enjoying a game in the tribble-infected recreation room against a Yeoman. (TOS: "The Trouble with Tribbles"; DS9: "Trials and Tribble-ations") On the next mission, he beamed Kirk, Spock and Doctor Leonard McCoy to meet Bela Okmyx on the surface of Sigma Iotia II on stardate 4598.0. (TOS: "A Piece of the Action")
He was in the engineering room when a group of Kelvans hijacked the starship and temporarily neutralized and reduced him into a small dehydrated porous cuboctahedron solid on stardate 4658.9. He was restored after Kirk, Spock, McCoy, and Scott regained control of the Enterprise. (TOS: "By Any Other Name")
He beamed aboard Commodore Bob Wesley to the Enterprise on stardate 4729.4 when the M-5 computer was installed on the vessel. (TOS: "The Ultimate Computer") He was part of the security detail for the Arret landing party on stardate 4768.3. When Kirk, Spock, McCoy, and Doctor Ann Mulhall beamed over to the planet, Sargon prevented him from joining along. (TOS: "Return to Tomorrow") He was in the transporter room with Lieutenant Leslie and was rendered unconscious by Gary Seven during the time traveling mission to 1968. (TOS: "Assignment: Earth")
He was the communications officer on stardate 4842.6 when Spock was in temporary command of the Enterprise on a mission to deflect an asteroid from colliding with the planet Amerind. (TOS: "The Paradise Syndrome") He escorted the Romulan commander to the bridge after she beamed aboard with Spock on stardate 5027.3 and witnessed the bridge crew's successful evasion of the three Romulan battle cruisers. (TOS: "The Enterprise Incident") He shadowed Mary Janowski after the Enterprise rescued the orphans of the Starnes Exploration Party on stardate 5029.5. He was posted by the turbolift doors on the bridge when the orphans temporarily hijacked the starship. (TOS: "And the Children Shall Lead")
On stardate 5121.5, the Vians created an illusion of Lemli and Scott outside a research station on the surface of Minara II in an attempt to trick Kirk, Spock, McCoy, and the empath Gem. (TOS: "The Empath") He was stunned unconscious on stardate 5431.4 when the Eymorg Kara appeared and removed Spock's brain. (TOS: "Spock's Brain")
When Kirk discovered an assassination plot against Ambassador Kollos on stardate 5630.7, he teamed up with Kirk, Spock, McCoy, and Leslie in response to the threat and ensured that no harm came to the Medusan ambassador. (TOS: "Is There in Truth No Beauty?") On stardate 5693.2, he attended a memorial service for Kirk when the Enterprise was ensnared in a Tholian web. He restrained a crewman who had succumbed to the effects of the interphase and led him to sickbay (TOS: "The Tholian Web") He witnessed Kryton commit suicide in main engineering after the Elasian guard sabotaged the Enterprise's dilithium crystal converter assembly. (TOS: "Elaan of Troyius") He escorted Kang and his surviving Klingon crew when they were confined to the lounge on Kirk's orders. (TOS: "Day of the Dove")
He joined the landing party on Scalos while the Enterprise investigated a mysterious distress call from the unseen Scalosians on stardate 5710.5. (TOS: "Wink of an Eye") He was stunned by Doctor Sevrin's ultrasonic waves when his followers seized control of the Enterprise and headed for the planet Eden on stardate 5832.3. (TOS: "The Way to Eden") He was miniaturized and placed into temporary stasis by Flint on stardate 5843.8. After Kirk's successful plea, he was restored to normal. (TOS: "Requiem for Methuselah")
He was posted as a security guard at the Elba II asylum on stardate 5718.3 and observed Garth of Izar's successful medical treatment by Governor Donald Cory. (TOS: "Whom Gods Destroy") He saw Lieutenant Mira Romaine faint on the bridge when the Enterprise encountered the Zetarians on stardate 5725.3 and was at the engineering station when the ship approached the planetoid Memory Alpha. (TOS: "The Lights of Zetar")
On stardate 5730.2, he was on the bridge and attempted to apprehend Lokai of Cheron under Kirk's orders. When the attempt failed, he fired a phaser at him but was unsuccessful because of a protective shield surrounding both Lokai and Bele. (TOS: "Let That Be Your Last Battlefield") He saved the lives of Kirk, McCoy, and Lieutenant Hikaru Sulu when he fired his phaser on the Kalandan outpost's computer and disabled the replicas of Losira. (TOS: "That Which Survives") After the Enterprise made initial contact with an Excalbian replica of Abraham Lincoln on stardate 5906.4, Kirk signed his PADD. (TOS: "The Savage Curtain")
He was present at Spock's court martial on stardate 5928.5. He was ordered to bring Doctor Janice Lester to testify, not knowing that she had already switched her body with Kirk's through a life-entity transfer machine. After Spock, McCoy, and Scott were sentenced to death for the charge of mutiny, he escorted them and Lester, who still had Kirk's persona, to the brig. (TOS: "Turnabout Intruder")
- In "Turnabout Intruder", Lester, while possessing Kirk's body, turns to Lemli at Spock's court martial.
- Janice-as-Kirk "Mister Lemli, have Doctor Janice Lester brought here."
- Lemli: "Aye, sir."
- "Who Mourns for Adonais?"
- "The Doomsday Machine"
- "The Changeling"
- "The Deadly Years"
- "I, Mudd"
- "The Trouble with Tribbles"
- "Bread and Circuses"
- "A Private Little War"
- "The Gamesters of Triskelion"
- "A Piece of the Action"
- "By Any Other Name"
- "Return to Tomorrow"
- "The Ultimate Computer"
- "Assignment: Earth"
- "Spectre of the Gun"
- "Elaan of Troyius"
- "The Paradise Syndrome"
- "The Enterprise Incident"
- "And the Children Shall Lead"
- "Spock's Brain"
- "Is There in Truth No Beauty?"
- "The Empath" (as an illusion only)
- "The Tholian Web"
- "Day of the Dove"
- "Wink of an Eye"
- "That Which Survives"
- "Let That Be Your Last Battlefield"
- "Whom Gods Destroy"
- "The Lights of Zetar"
- "The Way to Eden"
- "Requiem for Methuselah"
- "The Savage Curtain"
- "Turnabout Intruder"
Roger Lemli was played by Roger Holloway, a regular extra who appeared in the second and third seasons of the Original Series. Holloway did not receive onscreen credit for the role and had one brief line of dialogue in "Turnabout Intruder", the final episode.
The recurring character did not have a set identity until Scott referred to him as "Roger" in "The Changeling", the same first name as Holloway. Kirk addressed him clearly as "Mister Lemli" in "The Lights of Zetar" and "Turnabout Intruder", although the captain referred to him less clearly in "The Savage Curtain". Kirk referred to him just by rank, "Ensign", in "The Ultimate Computer".
According to the Star Trek Encyclopedia (4th ed., vol. 1, p. 459), Lemli was a reference to the daughters of William Shatner and his production company Lemli Music. The name was a combination of the first names of Shatner's three daughters: Leslie, Melanie and Lisabeth. Shatner later chose "LEMLI" for his vanity license plate in California.