Summary

• Big cast changes on Criminal Minds caused fans to feel upset, like when JJ left season 6 due to financial reasons.
• JJ's return was supported by fan outcry and she became even more important in Season 7, bringing closure to her story.
• Despite struggles with pay disparities, A.J. Cook remained a leading character through the show's 15 seasons and future revival.

Criminal Minds was no stranger to cast turnover, losing key protagonists and going through a number of seasons in which team members seemed to arrive and leave within the same year. Many departures caused a stir among fans, and the reasons became well known, including the dismissal of Thomas Gibson after an alleged on-set altercation and the early loss of Mandy Patinkin as Jason Gideon over the show's content. One that was nearly as dramatic, however, was the departure and later return of A.J. Cook's Jennifer Jareau, better known as JJ.

As part of a mid-series shuffle based partially on budgetary constraints, Cook's character was written off the show despite her seniority and through no fault of her own. More interesting, however, is that she was brought back less than a season later. So, why did JJ leave Criminal Minds? Here are the on and off-screen stories behind A.J. Cook's departure from Criminal Minds.

Updated on April 22, 2024, by Katie Doll: JJ is one of the most popular members of the BAU, and her departure felt unfair to many fans. We've updated this article to include more details about why JJ left Criminal Minds, her return to the series, and A.J. Cook's behind-the-scenes efforts to receive equal pay. We've also updated this article to bring it up to current CBR standards.

Who Was Criminal Minds' JJ?

Jennifer Jareau was a member of the original BAU team on Criminal Minds since the first season. JJ first appeared in the second episode of the series, titled "Compulsion," as the Behavioral Analysis Unit's liaison with local police and the media. JJ didn't work as a profiler at first but as an integral member of the team who accompanied them in most cases. JJ even went on a date with Spencer Reid once. However, their relationship never became more than a close friendship, and JJ and Reid's relationship became one of the most beloved on the show. Once she returned to Criminal Minds, JJ assumed the role of a profiler -- continuing her work with the BAU in the field.

• JJ grew up in a small town in Pennsylvania.
• While at school, she was the captain of the varsity soccer team her senior year.
• JJ eventually earned an athletic scholarship to the University of Pittsburgh.

JJ played a crucial role in the episode "North Mammon" from Season 2, even though she hadn't shown any interest in becoming a profiler at the time and instead preferred her role as a liaison. JJ met her future husband, William LaMontagne, while working on a case with the BAU in the episode "Jones," also from Season 2. They had two children together over the course of the show, and JJ's role as a working mother became an important part of her character. JJ's character development is one of the best in Criminal Minds, and the fans enjoyed watching her grow and overcome different obstacles throughout the series. And yet, why did JJ leave Criminal Minds and the BAU team?

Why Did JJ Leave Criminal Minds in Season 6?

Despite being a rather foundational member of the BAU team, JJ was written off of the series during most of Season 6. But before anyone asks if JJ died -- she was still alive and well. The in-fiction reason was her forced transfer to the Pentagon, which was in turn a cover story hiding her real work on a task force in the Middle East. Apparently, the Pentagon job had been offered to JJ multiple times before, though it's unclear if those instances were also cover stories for similar secret work. Erin Strauss forces JJ to take on the job, and not even Hotch can help her stay with the team. The real-world reason for Cook's exit was less dramatic, though. The studio was looking to reduce costs, so it let go of both Cook and fellow Criminal Minds star Paget Brewster.

• JJ was inspired to join the FBI after hearing a lecture from David Rossi.
• JJ had a sister who sadly died by suicide, something she still has a hard time talking about.
• JJ returns briefly to Criminal Minds after her departure, and is one of the few people to know that Prentiss faked her own death.

While Brewster stayed on for most of Season 6, Cook was given two episodes to wrap up her storyline. JJ's brief return in Season 6 was thanks to the numerous letters CBS received from fans demanding they bring JJ back to give closure to her story, proving just how popular and beloved her character was. While financial reasons were the biggest factor in the decision not to pick up Cook's contract, some speculated that she had chosen to leave for the standard "creative differences" that are often cited when an actor and show part ways. Others viewed her dismissal alongside Brewster's reduction as a sexist decision, and there was even some speculation that some executives wanted "new women" on the show. While Brewster told The AV Club that the network was "not particularly kind to women" and pointed to the significantly increased pay of her and Cook's replacement, Rachel Nichols, the generally accepted reason is still strictly financial.

When Does JJ Come Back to Criminal Minds?

Fortunately, Cook wasn't gone for long. The Season 7 premiere saw the return of both JJ and Brewster's Emily Prentiss to the BAU. JJ even reveals she took the necessary training to become a profiler and a field agent, and returns to the BAU team in a new position. Her return was bolstered by the outpouring of fan support after the announcement of Cook's departure -- no one except the studio seemed willing to let JJ go. JJ's in-fiction reason for her departure continued to play an important role in the series, and her time at the Pentagon becomes central to the overarching storyline in Criminal Minds Season 8.

• As JJ becomes a profiler and field agent, her duties as a liason for the media and the local police are shared between Garcia and Hotch.
• Reid resents JJ and Prentiss for not telling him Prentiss faked her own death, but he eventually forgives them.
• JJ receives more protagonism once she returns in Season 7, and by the end of the season, JJ and Will get married.

Cook's return didn't mean much of an improvement for women's wages on the series. In 2013, ahead of Season 9, Cook and co-star Kirsten Vangsness (who played Penelope Garcia) nearly refused to renew their contracts. CBS had made final offers to the main cast, which Cook and Vangsness reportedly were upset with due to being paid less than half of what their male co-stars were paid. It took more than two months for Cook and Vangsness to receive parity with male cast members. This came just a few years after Cook and Brewster's roles were significantly reduced for cost purposes, leaving Vangsness as the only full-time female cast member for a while. Evidently, Criminal Minds had a long history of undermining its female characters and the actors who play them.

Cook stayed on as one of the leading characters for the remainder of the original show's 15-season run and is now part of the cast of the revival Criminal Minds: Evolution, also known as the 16th season of Criminal Minds. Despite the potential for ill will between her and the network, Cook saw the fan support as a silver lining and was able to build a continued career after the experience. While the situation was obviously less than ideal, corrections were quickly made and Criminal Minds fans were able to see JJ not only continue her story but grow in importance until Criminal Minds: Evolution came into fruition. Filming for Criminal Minds: Evolution Season 2, or Criminal Minds' 17th season, began in January 2024, with AJ Cook set to return as JJ.

All 15 seasons of Criminal Minds are streaming on Hulu and Paramount+. Criminal Minds: Evolution is now streaming on Paramount+.