The character "Penelope Garcia" was supposed to be in only one episode, but she tested so positively that she was added to the main cast.
Most of the playful banter between Morgan (Shemar Moore) and Garcia (Kirsten Vangsness) stems from the way the actor and actress talk to each other in real-life.
Matthew Gray Gubler does not wear matching socks, because he thinks it's unlucky. In a few of the episodes, you can see his mismatched socks.
When David Rossi (Joe Mantegna) joins the team, he makes a comment that their offices are better than "that bunker", out of which the B.A.U. used to work. The comment isn't metaphorical. The actual B.A.U. (in its many earlier incarnations and titles) used to operate out of a bunker, former F.B.I. Director J. Edgar Hoover had built below F.B.I. Headquarters in Quantico, Virginia.
The character of Special Agent Reid was a child prodigy, having graduated from high school at age twelve. Matthew Gray Gubler, describing what may form his character's genius, has said that Reid may have Asperger's syndrome, and perhaps even be mildly schizophrenic. Reid's mother was schizophrenic herself.
J.J.'s children are played by A.J. Cook's actual children, Mekhai Andersen and Phoenix Anderson. Thomas Gibson's son Travis Gibson appeared in an episode that he directed. Joe Mantegna's daughter Gia Mantegna made a few guest appearances.
When Matthew Gray Gubler initially auditioned for the show, he was told that he was not right for the part. However, he was called back to audition again a few more times and was consistently told that he wasn't right for the part. After several more auditions, Gubler was eventually given the role.
Penelope Garcia was hired by the F.B.I. as a technical analyst after she was arrested for illegally hacking into their computer database. She was given the choice of working for the Bureau or being sent to federal prison.
David Rossi has mentioned he knows Ringo Starr. There is even a picture of him and Starr on Rossi's desk. Joe Mantegna and Ringo Starr are friends in real-life.
Dr. Spencer Reid has an I.Q. of 187, an eidetic memory, and can read up to twenty thousand words per minute.
In the show's opening credits, mug shots of real-life serial killers and mass murderers are shown. Among the killers shown are John Wayne Gacy, Charles Manson, Richard Ramirez ("The Night Stalker"), Theodore John Kaczynski ("The Unabomber"), Timothy McVeigh, Lee Harvey Oswald, and Susan Smith.
Kirsten Vangsness is the only main cast member to also be in the main cast of the short-lived spin-off, Criminal Minds: Suspect Behavior (2011).
During filming, Paget Brewster would often stash things in her boots, such as her phone, scripts, and cigarettes.
Dr. Spencer Reid holds doctorate degrees in Mathematics, Chemistry, and Engineering, as well as Bachelor's Degrees in Psychology and Sociology. He is studying for a Bachelor's degree in Philosophy as well.
Before joining the B.A.U., Derek Morgan was a highly decorated member of the Chicago Police Department's bomb squad, and is an expert at defusing explosives.
The original title for the show was "Quantico", and the pilot was filmed in Vancouver, Canada. In the "Quantico" script, Jason Gideon was named Jason Donovan.
Kirsten Vangsness isn't formally included in the main cast until the second season.
Rossi's full name is David Stephen Rossi. Gideon named his son Stephen after Rossi.
Reid writes a letter to his mother every day so he doesn't feel so guilty about not visiting her.
Matthew Gray Gubler was once photographed by famed photographer Mia Grace, who had a small part in the series' pilot episode.
In a 2012 interview, in New York Magazine, Mandy Patinkin said that he greatly regrets ever having accepted his role on the show: "The biggest public mistake I ever made was that I chose to do 'Criminal Minds' in the first place. I thought it was something very different. I never thought they were going to kill and rape all these women every night, every day, week after week, year after year. It was very destructive to my soul and my personality. After that, I didn't think I would get to work in television again. I'm not making a judgment on the taste (of people who watch crime procedurals). But I'm concerned about the effect it has. Audiences all over the world use this programming as their bedtime story. This isn't what you need to be dreaming about. A show like Homeland (2011) (on which Patinkin began appearing in 2011) is the antidote. It asks why there's a need for violence in the first place."
Elle Greenaway is fluent in Spanish. Emily Prentiss and Spencer Reid are both fluent in multiple languages.
One of the signature images of this show is the brief shot of a business jet flying the team to a crime scene. Often these shots are paired as book-ends at the beginning and end of an episode, with voice-over of a cast member reciting a famous quotation. The jets shown are always Gulfstream products, including models G-IV, G-V, and G-450. Occasionally the shots are reversed left-to-right (for example, episodes "A Thin Line" and "I Love You, Tommy Brown"). The tail numbers shown are often registered to Gulfstream Corporation, indicating that the shots are taken from Gulfstream publicity materials.
CBS aired an episode after Super Bowl XLI (2007) in the hopes of transforming the series from a relatively modest hit into a top ratings performer. The episode featured cameos by Super Bowl announcers Jim Nantz and Phil Simms.
Kate Callahan (Jennifer Love Hewitt) left the show after one season. She was replaced on the team by Dr. Tara Lewis (Aisha Tyler). Hewitt and Tyler played best friends and co-workers on Ghost Whisperer (2005).
Agents Kate Callahan and Elle Greenaway are the only agents on the team to always be referred to by their first names. The other agents throughout the series, Jason Gideon, Aaron Hotchner, Emily Prentiss, Derek Morgan, Spencer Reid, Ashley Seaver, Jennifer Jareau, Penelope Garcia, Alex Blake, Tara Lewis, Luke Alvez, and Stephen Walker, are almost always referred to by their last names. However, Agents Hotchner and Jareau are always called by their nicknames: Hotch and J.J., respectively.
Mandy Patinkin's characters in this show and Dead Like Me (2003) have many similar interests. They are both shown to be capable and enthusiastic chefs, and have an affinity for art.
Derek Morgan is from Chicago, and has Northwestern University football memorabilia on his office shelves.
It was the network's decision to cast Damon Gupton for the show. Producer Erica Messer had to create the character for him to play.
Jason Gideon and David Rossi were the two Agents who formed the basis for the B.A.U. The characters, as young men, were featured in the story "Nelson's Sparrow". But the older characters were never featured together, and the actors who played them (Mandy Patinkin and Joe Mantegna) have never acted together.
As of season thirteen, Matthew Gray Gubler and Kirsten Vangsness are the only two cast members to have remained on the show since its inception, with other members having left the show (and return in some cases), or be fired. However, because Penelope Garcia was a recurring role during the first season, it is Matthew Gray Gubler who holds the record as the longest-running main cast member of the series.
The only series in the "Criminal Minds" franchise without an Oscar nominee in the top-billed role. Forest Whitaker (Criminal Minds: Suspect Behavior (2011)) won Best Actor for The Last King of Scotland (2006), and Gary Sinise (Criminal Minds: Beyond Borders (2016)) earned a Best Actor in a Supporting Role nomination for Forrest Gump (1994).
The third Touchstone, later ABC Studios-produced show not to be aired on ABC. The other two ABC Studios-produced shows that have aired and/or still airing on CBS are: The Amazing Race (2001) and Ghost Whisperer (2005).