Grey was a Federation historian who participated in historical research expeditions using the Guardian of Forever on the time planet.
In 2269, Grey, along with colleague Aleek-Om, studied data on the history of Orion, at the dawn of its civilization, and Vulcan, during the 2230s. (TAS: "Yesteryear")
The voice for Grey was performed by Majel Barrett. Her name was not spoken on screen but rather comes from the script.