Emily Prentiss

Emily Prentiss is a Special Agent with the BAU.

Background
In her first appearance, she recognizes Hotch from one of his first commands: security clearances for her mother, a US diplomat. Her arrival surprises both Hotch and Gideon, as neither of them had signed off on the transfer. Prentiss insists her parents have not pulled strings for her. Ultimately, she joins the team at the end of episode 209 ("The Last Word") on a probationary basis as a replacement for Agent Elle Greenaway. She is a graduate of Yale and has been working for the FBI for little under ten years, primarily in the Midwest. Due to spending her early life with her parents on diplomatic missions to the Middle East, she speaks fluent Arabic and is familiar with that area's local culture. She also speaks some Russian, Spanish, French, and Italian. She appears skilled at chess, and it is possible that she is better at the game than Reid. JJ once asked Prentiss how she could handle the stress from being with the BAU, especially since her last position was a desk job. Hotch concurred that she had "never blinked," and Prentiss could only reason that she "compartmentalizes better than most." ("Revelations") After a bad date in the following episode, she admits to Derek Morgan that she is a "nerd," despite how much she tries to hide it. For this reason, she hasn't had much success romantically. She discovers that she and Morgan share similar tastes in books when they begin discussing Kurt Vonnegut, particularly Slaughter House 5.

On the Job
At the end of season 2, BAU section chief Erin Strauss reveals to Emily that she arranged for her to join the BAU, contrary to Emily's belief that she was accepted on her own merit. Strauss asks Emily to sabotage Hotch's career by spying on him and relaying confidences back to Strauss, especially concerning Elle Greenaway's shooting of a suspect and Reid's struggle with narcotics. She seems to consider this offer, and the season ends with a cliffhanger until the second episode of season 3, in which she resigns from the FBI to avoid betraying Hotch. She decided later not to resign.

Season Three
Emily has previously told Hotch that she thinks politics "makes people distrustful" and "tears families apart," ("Sex, Birth, Death") implying that her home life as a child was not pleasant due to her mother's job. After some convincing from Hotch she returns to the team in the next episode, her resignation having never gone through system due to technical interference from Garcia, and the issue has not been brought up since. Upon her return, Section Chief Strauss remarks that neither Prentiss, Hotch, nor the rest of the team would be able to climb the ladder to the top because of all this, thus putting an end to some of Prentiss's future ambitions. In episode 319 ("Tabula Rasa") a high school photo reveals that Emily was a goth or emo. Also, in episode 312 ("3rd Life"), she implies to Hotch that she smoked as an adolescent as a way to rebel against her parents. In the season 3 finale "Lo-Fi", she shoots and kills an armed suspect after the suspect shoots a New York police officer.

Season Four
In season 4 episode 3 (Minimal Loss) she and Reid are held hostage by a religious cult. When the cult leader finds out that one of them is an FBI agent, Prentiss admits her identity, partially to protect Reid, and ends up getting beaten by the cult leader. Prentiss antagonizes the leader by twice repeating "I can take it" to keep the rest of the team from coming in, knowing that they are listening via bugs and that it would put everyone inside of the building in danger. Later, Prentiss reassures Reid that it was not his fault and asks him not to feel guilty.

Season Six
In The Thirteenth Step, Prentiss learns from a former colleague at Interpol, Sean McCallister, that Ian Doyle, an apparently highly dangerous criminal, has escaped from his North Korean prison and gone off the grid and apparently killed a man and stole his car. Sean warned her that he might come after her and that everyone is in danger. In the beginning of Sense Memory, in her apartment, when the phone rings and the caller ID is unknown, Prentiss lets it go to message and listens to the recording. The caller, presumably Doyle, is completely silent and hangs up. In response, Prentiss sets up some noise-traps near all entrances and exits in the apartment, sits down in the hallway with a gun, turns off the lights and waits.

When Prentiss returns to her apartment after a case, she finds a package by her door. When she opens the package, it turns out to contain a small, purple-white flower. There is a flashback to some time earlier when she is working in a flowerbed filled with the same flowers, apparently by a mansion somewhere in France. When authorities, presumably Interpol, arrive and drive away with her, Doyle watches her from a balcony. He calls someone and tells the other person to "stay on on top of [it]". As he is arrested by English-speaking authorities, he looks down at one of the flowers that Prentiss dropped.

In Valhalla, Doyle resurfaced in DC and began killing people connected to his case as well as their families. During the investigation, he kills one of Prentiss' former colleagues, Tsia Mosely. It is also revealed that Prentiss, Sean, Tsia, and two other colleagues were part of a team assembled by Interpol that profiled terrorists and helped apprehend them, codenamed JTF-12.

In Lauren, Prentiss goes after him alone. As she attacks him and his men near The Black Shamrock, a bar in Boston at which he and Prentiss (as "Lauren Reynolds") first met. As she holds a submachine gun at his men, he flanks her and shoots her in the abdomen. She survives, wearing a bullet-proof vest, and is abducted and taken to the group's HQ. She is tortured and beaten as Doyle recounts what happened after his arrest: he was taken to a prison in North Korea, where he resisted in interrogation for two years, hoping to see his son, Declan, again. When he was shown a series of pictures of Declan and his legal guardian being executed by a mostly unseen figure, he broke down completely and would remain there for another five years. Unbeknownst to him, the pictures were actually staged by Prentiss in order to save Declan from his father's life. The BAU, having found the photos, notices that the nails of the hand holding the gun are completely bitten down; Prentiss was a compulsive nail biter when nervous. Obtaining the address of the house, they conduct a stealth raid on it, killing all of Doyle's men. As Doyle, furious to learn how he was deceived by Prentiss, begins furiously beating her. She gets the upper hand and knocks him to the floor with a wooden stick. Once she drops it, Doyle grabs it and stabs it into her abdomen. Hearing the gunfire approach, he escapes and isn't seen for the rest of the episode. The BAU arrive and take Prentiss to a hospital, where they are told that she didn't survive. They all attend Prentiss' funeral. Her headstone is marked "Fidelity, Bravery, Integrity", the motto of the FBI. In the final scene, JJ is seen approaching a woman (whose face is unseen) in France and giving her passports for three different countries and a bank account in each one. The woman's hands are shown to the viewers to have completely bitten-down nails, implying that it is Prentiss, who is alive and has faked her own death in order to go into hiding from Doyle. The characters miss her dearly.

On May 28, 2011, it was announced that Paget Brewster would be returning to the series, meaning Prentiss will be back for season seven.