After Worf's birth, Kahlest came into the House of Mogh as a nurse for the infant Worf. As a young and attractive woman she caught the eye of K'mpec, however she considered him to be too fat to be a suitable mate.
In 2346, Kahlest accompanied Mogh, Kaasin, and Worf to the Khitomer Outpost so that Mogh could follow up on suspicions that a Romulan collaborator had gone to Khitomer. She was one of the few Klingons to survive when the Romulans attacked the outpost. After her rescue by Starfleet, it was Kahlest who convinced Sergey Rozhenko that if Worf was returned to the Klingon Empire that his life would be in danger as the allies of the Romulan collabator would target the young Klingon for assassination. She convinced Rozhenko to adopt Worf as his son. (TLE novel: The Art of the Impossible and TNG episode: "Sins of the Father")
After her return to Qo'noS, Kahlest spent the next 20 years in seclusion in a home in the old quarter of the First City. When Worf returned to Qo'noS to answer charges that his father had been a traitor, Captain Jean-Luc Picard found Kahlest and brought her before the High Council to refute the charges that Mogh was a traitor. However the council was unwilling to back down, and Worf agreed to accept discommendation (TNG episode: "Sins of the Father")