Background

BACKGROUND

When the series premiered in September 2005, it featured FBI Agents Jason Gideon, Aaron Hotchner, Elle Greenaway, Derek Morgan, Spencer Reid, Jennifer "J.J." Jareau, and Penelope Garcia. For season one, Garcia was not a main cast member, but rather had a recurring role, although she appeared in most episodes. In 2006, at the start of season two, Lola Glaudini announced her departure from the show, as she wanted to return home to New York City. Paget Brewster replaced her in the role of Emily Prentiss.

At the start of season three, Mandy Patinkin announced his departure from the show because he was deeply disturbed by the content of the series. He left letters of apology for his fellow cast members, explaining his reasons and wishing them luck. Joe Mantegna replaced him as David Rossi, a best-selling author and FBI agent who comes out of retirement. During season three, A.J. Cook became pregnant with her first child. Her pregnancy was written into the show. Cook's son, Mekhai Andersen, has been written into a recurring role as Jennifer's son Henry. Cook's void was filled by Meta Golding, who played Jordan Todd, an FBI agent who works with the agency's Counter Terrorism Unit. In season six, Jennifer is forced to accept a promotion at The Pentagon, causing her to leave the BAU.

Later that season, Emily is seemingly killed off. Although she survives, she does not appear for the rest of the season. Cook and Brewster were both replaced by Rachel Nichols as Ashley Seaver, an FBI cadet. CBS's decision to release Cook and Brewster from their contracts resulted in numerous fans writing angry letters to the studio and signing protest petitions. CBS rehired Cook and Brewster as Jennifer Jareau and Emily Prentiss, respectively; Nichols was released. In February 2012, Brewster announced her departure from the show after the seventh season. She was replaced in the eighth season by Jeanne Tripplehorn, who played Alex Blake, a linguistics expert. Later in season nine, Paget Brewster made a special guest appearance, reprising her role as Emily Prentiss in the 200th episode.

After two seasons, Tripplehorn was released from the show. Jennifer Love Hewitt joined the cast as Kate Callahan, a former undercover FBI agent who joins the BAU. During season ten, Jason Gideon was killed off-screen. Executive producer and showrunner Erica Messer said CBS and ABC Studios were fine with the decision because it was clear that Patinkin would not come back again, but the show would feature him in a flashback if he were ever to return in the future. Following the conclusion of season ten, Hewitt and Cook announced that they'll both be on hiatus from the show due to their pregnancies. Hewitt did not return for season eleven, while Cook returned after the first seven episodes of season eleven. Aisha Tyler, who plays Dr. Tara Lewis, joined the show at the start of season eleven.

Later that season, Shemar Moore, who plays Derek Morgan, left the show after eleven seasons. He had thought to leave in the previous season when his contract ended but was convinced to stay to give his character a proper sendoff. Messer said the initial thought was for Moore to do six episodes, but when that didn't feel like enough, they settled on Moore doing the first eighteen episodes of that season and he departed in March 2016. He is replaced in the twelfth season by Adam Rodriguez, who plays Luke Alvez, a Fugitive Task Force Agent. A week after Moore left, Paget Brewster, who plays Emily Prentiss, made her second special guest appearance since leaving in season seven, her first being in season nine. In season twelve, Brewster will once again be a series regular on the show.

On August 10, 2016, it was announced that former recurring star Aisha Tyler would be promoted to series regular for the twelfth season. The next day, it was reported that Thomas Gibson, who portrays Aaron Hotchner, had been suspended from and written off the show for at least one, most likely two episodes in the twelfth season due to an on-set altercation with one of the producers. On August 12, 2016, Gibson was fired from the program due to this incident. On September 30, 2016, it was announced that Gibson's character would be replaced by Damon Gupton, who will play Special Agent Stephen Walker, a seasoned profiler from the Behavioral Analysis Program (the counterintelligence division of the FBI) who will bring his spy-hunting skills to the BAU.