Jennifer "Jenny" Shepard was a former NCIS Special Agent and also the former Director of NCIS who led the agency from September 2005 up until her death in the field in May 2008.
The daughter of Jasper Shepard and an unnamed civilian woman, Jenny along with her unseen sister Heather were both presumably born and raised in Los Angeles with the family relocating to Washington D.C. after Colonel Shepard was reassigned to the Pentagon.
During his time at the Pentagon, Colonel Shepard was accused of taking a bribe but died while under investigation with his death being recorded as a suicide.
Jenny however refused to accept the suicide ruling and later became fixated on the idea that French-born international arms dealer, René Benoit AKA "La Grenouille" or "The Frog" was responsible for her father's murder and as such, she sought to capture the Frog by any means necessary, even going so far as to devote ten years to her life in the hope of arresting him.
At some point, Jenny, fueled by the need to make her dream of arresting the Frog a reality joined NIS/NCIS where in 1999 and as an NCIS Special Agent, she worked with NCIS Special Agents Leroy Jethro Gibbs and Agent William Decker on a covert mission in Paris involving the assassination of Russian arms dealer, Anatoly Zhukov and his fiancée, Svetlana Chernitskaya.
While Decker served as the handler, Gibbs was assigned to eliminate Zhukov and Jenny was sent to kill Svetlana and although the mission was considered a success due to Gibbs killing Zuchov, Jenny had failed to neutralize Svetlana because at the time, Jenny, a rookie agent, did not possess the emotional capacity required to assassinate someone.
This ultimately prompted Jenny to let Svetlana go, a failure that would ultimately cost Decker and Jenny their lives some years later.
Whilst in Paris she and Gibbs became lovers, remaining so during further assignments in Serbia, Italy and London. However, their relationship soon soured and she eventually left Gibbs, apparently to further her career but also because of his inability to commit to a future together.
While on missions in Europe, Jenny also met and befriended Mossad officer Ziva David with Ziva saving Jenny's life during a mission in Cairo, Egypt two years prior to NCIS Season 3.
At some point, Jenny returned to the States and presumably remained in some kind of administrative position at NCIS.
NCIS Season 3Edit
At the start of this period, Jenny was appointed the new Director of NCIS, replacing Thomas Morrow. She makes it clear to Agent Gibbs that despite their romantic history, "there won't be any off the job" between them. She and Gibbs frequently push each others' buttons and get into disputes over cases, but it is clear they also highly understand and trust each other. Several flashbacks of their romantic history are shown in this season.
NCIS Season 4Edit
Jenny pursues the man she blames for her father's death, international arms dealer René "La Grenouille" Benoit, by using agency resources to track and deceive him covertly - such as sending "Very" Special Agent Anthony DiNozzo, in an undercover capacity as "Anthony DiNardo", to gain the trust of Jeanne Benoit, La Grenouille's daughter. DiNozzo and Benoit genuinely develop feelings for each other, greatly complicating matters for all involved.
At the end of this period, Grenouille exposes Tony's cover, and endures an attempt against Jeanne's life, which convinces him he is in serious danger to ask NCIS for help in a secret meeting as Grenouille appears unexpectedly at Jenny's house. She turns him down, and he is later found floating near his houseboat, with a single gunshot wound to the head.
NCIS Season 5Edit
Jenny conceals the fact that she is fatally ill from her subordinates. When Agent Decker, a former team member of hers on an operation using the code word "Oshimida" is killed, she enlists former senior field agent Mike Franks to pursue the investigation privately with her. They pursue the investigation to a small diner in the Mojave Desert. She admits to Franks that she regrets leaving Gibbs years ago, and they also discuss her illness. She is killed in a shootout at the diner with thugs affiliated with Svetlana Chernitskaya, the handler and fiance of Anatoly Zhukov, the Russian arms dealer killed by Jenny, Decker, and Leroy Jethro Gibbs in 1999.
Gibbs deduces from forensics that she killed several of her attackers singlehandedly and "put up one Hell of a fight". Franks tells Gibbs that "her last stand was to protect you".