Janet was romantically involved with James T. Kirk in 2261, with the relationship advancing far enough that Kirk announced their engagement to be married. However, they both mutually decided to end the relationship, while at the Moonbeam Club, when they realized that they were both too dedicated to their respective careers to devote time to each other.
Janet was eventually assigned to a remote outpost on Aldebaran III, where she met her co-worker and future husband, Theodore Wallace. After Theodore died, Kirk sent Janet a stargram, but otherwise had lost contact with him until 2267.
Wallace was assigned to the USS Enterprise during its mission to Gamma Hydra IV. When a landing party, including Kirk, was subjected to a radiation disease which caused hyper-aging, Janet worked with CMO Leonard McCoy on developing an adrenaline-based cure which returned all infected to their rightful physical condition.