The popular CBS drama series Criminal Minds centers on the Behavioural Analysis Unit of the FBI, which, through criminal profiling, helps to track down and stop serial killers and criminal behavior. The main team of the BAU changes a lot throughout the series, as does the supporting cast. As Criminal Minds follows a case per episode structure, there are many opportunities for actors to guest star in one or two episodes.
The guest stars on the show have ranged from newcomers to the industry to recognizable faces with acclaimed careers behind them. Whether they were well known when they appeared on the show, or just getting their start, fans binge-watching the show today would be able to pick out many known faces amongst Criminal Minds' guest stars.
10 Cameron Monaghan In "The Boogeyman"
Known for his recent roles as Ian Gallagher in the long-running drama Shameless and Jerome Valeska in the DC hit Gotham, Cameron Monaghan was just thirteen years old when he appeared in the second season of Criminal Minds. Monaghan's character, Jeffrey Charles is revealed to be the unsub, who is brutally murdering his classmates and covering up his kills with the skill of a much older, more experienced killer. Despite his young age, Monaghan gives a brilliant performance that makes the narrative of the episode even more harrowing.
9 Luke Perry In "Minimal Loss"
Luke Perry rose to fame in the '90s for his role as Dylan McKay on the Fox teen drama Beverly Hills, 90210 and was known to younger audiences for playing Fred Andrews in the CW series Riverdale. Perry appeared in the Season 4 episode "Minimal Loss" where he portrayed Benjamin Cyrus, the leader of a cult where the abuse of children was taking place. Prentiss and Reid go undercover but find themselves caught up in a hostage situation when Cyrus goes from his calm and collected façade to the controlling and violent unsub he has been accused of being.
8 Ben Savage Played A Young Jason Gideon
Ben Savage has been a prominent face of the small screen for many years. He rose to fame with his starring role as Cory Matthews in the 1993 sitcom Boy Meets World, which followed Cory and his friends as they went through high school and college. Savage reprised his role in the 2014 Disney channel show Girl Meets World. In the flashback episode, "Nelson's Sparrow," Savage portrayed a younger version of previous BAU agent Jason Gideon. Savage perfectly recreated the essence of the character, carrying himself in the same way that Mandy Patinkin did when he portrayed the character.
7 Jason Alexander In "Masterpiece"
Seinfeld's George Costanza was almost unrecognizable when he appeared in Criminal Minds' fourth season. Actor Jason Alexander portrayed Henry Grace, an extremely intelligent and narcissistic serial killer who harbored a grudge against the BAU due to Rossi previously arresting his brother.
Unlike other unsubs, Grace confessed to the murders he committed whilst letting the BAU know that he had captured five other people who will die every two hours if they cannot be found by the team. This knowledge makes the unsub feel superior like he has the upper hand, but of course, he is eventually outsmarted by Rossi and the team.
6 Tim Curry As The Prince Of Darkness
English actor Tim Curry, who is known for his beloved roles as Dr. Frank-N-Furter in The Rocky Horror Picture Show, Pennywise in the original version of It, and Wadsworth in Clue, guest-starred in Criminal Minds' fifth and sixth seasons as the unsub Billy Flynn, dubbed The Prince of Darkness. Flynn was a spree killer who would assault and murder entire families in the dark, leaving the children alive to let them experience the same trauma that he did in his youth. Curry's performance is a memorable one, with fans and the cast of the show labeling the Prince of Darkness as one of Criminal Minds' creepiest unsubs.
5 James Van Der Beek As Tobias Hankel
James Van Der Beek made a name for himself starring as the title character in The WB's teen drama Dawson's Creek. However, he showed a completely different side of his acting abilities in the second season of Criminal Minds. Van Der Beek played Tobias Hankel, an unsub with dissociative identity disorder, who immortalized the personality of his abusive, dead father. Hankel, who was initially believed to be a witness, is discovered to be the unsub by JJ and Reid. Whilst JJ is attacked by Hankel's vicious dogs, Hankel abducts Reid, holds him at gunpoint, and injects him with Dilaudid.
4 Jane Lynch As Diana Reid
Seasoned actress Jane Lynch has had a long, successful career on stage and screen with many accolades, including five Emmy Awards, under her belt. She is possibly best known for starring as cheerleading coach Sue Sylvester in the comedy series Glee.
Lynch appears in Criminal Minds across many seasons and portrays Dr. Spencer Reid's mother. Her character is diagnosed with schizophrenia early on in the series, with Spencer's wish to care for her himself becoming a large part of his storyline, especially in the twelfth season.
3 Michelle Trachtenberg In "Zugzwang"
Michelle Trachtenberg has been acting since she was a child and is known for her roles in the movie EuroTrip, as Buffy's sister Dawn in Buffy the Vampire Slayer, and as serial antagonist Georgina Sparks in the 2007 teen drama Gossip Girl. Trachtenberg portrayed the unsub, Diane Turner, in season eight's stand-out episode Zugzwang. Turner was jealous and obsessive, willing to die for the attention of someone she loved, which led to her being responsible for the death of Reid's girlfriend Maeve Donovan. Trachtenberg's performance was completely convincing and made her stand out amongst the other unsubs in Season 8.
2 Mark Hamill As The Replicator
Mark Hamill's name is recognizable to generations of movie fans, from his breakout role as Luke Skywalker in the Star Wars franchise. In Criminal Minds, Hamill took on the role of FBI agent turned serial killer John Curtis, also known as 'The Replicator'. The Replicator appeared throughout the show's eighth season. A copycat killer, he would recreate murders from cases that the BAU had already solved in an attempt to taunt them. The Replicator storyline and Hamill's performance are remembered by fans as one of the best of the show.
1 Aubrey Plaza As Cat Adams
Comedic actress Aubrey Plaza is probably best known for her role as April Ludgate, the sarcastic Pawnee Parks Department employee in the NBC sitcom Parks and Recreation. However, Plaza went down a darker route when she played talented assassin Cat Adams. Plaza first appeared in the episode Entropy, which is widely considered to be the best episode of Criminal Minds, and continued taunting the BAU, specifically Reid, in her guest appearances in seasons twelve and fifteen. Adams's quick wit and ability to almost match Reid intellectually made her, and Aubrey Plaza's appearances on the show some of the most memorable.