Born in the year 2247, she was a member of the Karidian Company of Players and the daughter of the company's founder, Anton Karidian, previously known as Kodos. Anton took care so that his daughter never learned of his past identity. However, not only did she do so, but she also became determined to silence all those who could connect her father to his past life. (TOS episode: "The Conscience of the King")
In 2266, the Karidian Company visited Planet Q and while there, Lenore took the opportunity to assassinate Thomas Leighton, one of the last few people still alive who could identify her father as Kodos. However, before his death, Leighton had told his old friend, Federation Starfleet officer Captain James T. Kirk of the starship USS Enterprise of his suspicions that Anton Karidian was in fact Kodos the Executioner.
Although initially sceptical, Kirk did begin his own investigation upon Leighton's death and arranged to have Enterprise ferry the actors to their next destination, calling in a favor from his old friend Jon Daily, captain of the Astral Queen, the company's original transport, in the process. While aboard the Enterprise, Lenore tried, unsuccessfully, to assassinate another member of the crew, Lieutenant Kevin Riley, but his survival was kept a secret and when she tried to kill Kirk with a phaser, her father stepped in front of him at the last moment. The realization that she had killed the one man she had spent all her life trying to protect destroyed what remained of her mind; she was taken into medical custody. (TOS episode: "The Conscience of the King")
By 2288, Lenore had been rehabilitated and was part of a group of volunteers that was helping rebuild on the planets Pavak and Oyolo. However, she came under suspicion when two delegates were murdered with an overloaded phaser and medication she was using. (TOS novel: Foul Deeds Will Rise)