Dannan Stuart was a Human woman, born in 2264 to Tommy Preston and Fran Stuart. She was the older sister of Peter Preston and the niece of Fran's brother Montgomery Scott. She was born shortly after her uncle departed on a five-year mission aboard USS Enterprise. On that occasion, Montgomery offered cigars to his crewmates, although Spock declined on the basis of the extreme illogic of smoking. (TOS novel: Enterprise: The First Adventure)

In A Time for War, A Time for Peace, Fran's name is given as "Clara".

When her Uncle Montgomery visited in the early 2270s, while he was supervising the refit of Enterprise, young Dannan commented that joining Starfleet and wearing a dull gray uniform didn't seem like something she wanted to do; however, she did end up training as an officer. When her brother was killed on a training mission, she attended his memorial service before returning to Starfleet Academy in 2285. (TOS comic: "Retrospect"; TOS novelization: Star Trek III: The Search for Spock)