She was seen sometimes picking him up after Gibbs and his team had solved a case or dropping him to a crime scene.
She was also noted for driving a silver Mercedes with Gibbs's colleagues, Anthony DiNozzo, Caitlin Todd, Timothy McGee and Ziva David often wondering who the woman was although they never personally confronted Gibbs about it.
NCIS Season 1
The Mysterious Red-Head first appeared in Yankee White (episode).
NCIS Season 2
She appeared in Heart Break (episode).
NCIS Season 3
The mysterious woman's final appearance to date was in the Season Three episode, Silver War (episode) where Gibbs was seen escorting her to the Elevators while DiNozzo and new team member, NCIS/Mossad Liaison Officer Ziva David looked on.