|“||I can get you anywhere. I own this place.||”|
— Calvin in "Green Light"
Shaw was a highly respected agent who worked for the FBI's office in Detroit, Michigan. He and his coworkers were assigned to dismantle a branch of the Russian Mafia that was operating in the area, and they used an informant named Elena Olegnova to help them infiltrate the organization. At some point during the operation, Shaw started a romantic affair with Olegnova, despite being married to another woman who was expecting their first child. When Olegnova got pregnant with his child too, Shaw decided to silence her by killing her, and he shot her in the uterus to ensure no one would find a trace of his unborn baby with her. He then pinned her murder on a rival gang. He initially got away with it, but six months after the murder, his wife gave birth to his son.
Wracked with guilt, and realizing that he needed to raise his son with a clean conscience, Shaw decided to turn himself in. He created a false story that Olegnova got greedy and started blackmailing the team, threatening to blow their covers if they didn't increase her paychecks. Believing an arrest would still endanger the lives of his teammates, Shaw had chosen to kill Olegnova to silence her. After turning himself in, he was stripped of his badge and imprisoned at Millburn Correctional Facility. In prison, Shaw survived his first few months by reading books from the prison library and isolating himself from most inmates. He developed a good reputation with the rest of the inmate population because he was responsible for the death of an informant, a job that is seen by most criminals as the lowest of the low. He later became a trusted member of a drug cartel that had an arm of operations in Millburn. Meanwhile, Shaw's case became a popular topic in the Bureau, with the story being used in training classes attended by Luke Alvez.
"[Prison] is our ocean. One day it's calm. The next day there are waves the sizes of mountains. It'll be hard, at first, but trust me, you shouldn't fight it. You just gotta learn how to survive."
Reid, who was imprisoned for the murder of Nadie Ramos, first recognizes Shaw as the latter is playing a game of chess with another inmate, and Shaw notices him as well. Later that night, he saves Reid's life when is about to be killed by Milos and his gang of cronies. The next day, Reid visits Shaw in his cell and they both introduce themselves. When Reid explains his knowledge of Shaw and why he is in prison, Shaw explains his reasoning for killing Elena. Then, Shaw asks Reid if he truly murdered Nadie, but he replies that he didn't. After learning from Reid that he likes to read books, Shaw tells him that living in prison will be hard at first, but he shouldn't fight it, and offers to help him learn how to survive. At the end of the episode, Shaw starts playing a round of chess with Reid between their cells, all the while consoling him.
"I helped you because I like you. You're interesting to me. But if you keep this up, keep thinking the normal rules apply in here, then I cannot help you."
As Reid and Shaw eat together in the cafeteria, they observe Frazier and Duerson approaching Luis Delgado and holding him at knifepoint with a shiv. Realizing they are about to assault him, Reid gets up, but Shaw stops him and warns that they are not going to hurt Luis, just teach him a lesson. Shaw explains that they are testing him and that the rules in prison are different. The next day, Reid notices Luis's absence in the cafeteria and asks Shaw about what happened to him; he replies that he had been taken to the infirmary with broken ribs. When Reid gets worried, he reminds him that it was a test. Then, Shaw tells Reid that, in prison, everyone is a psychopath and asks if he is a predator, or prey.
Unwilling to accept Shaw's claim that Frazier and Duerson were testing Luis, Reid gets up from the table and talks to Officer Peters about something. When Reid returns, Shaw asks him what he told Peters, and Reid replies that he was just thirsty. However, Shaw deduces that Reid snitched on Frazier and Duerson, a serious mistake to make in prison. He first tells Reid that he helped him because he likes him and found him interesting. He then warns that if he keeps believing that the rules of the outside world also apply in prison, then he can't help him. He wishes Reid good luck and leaves.
"The deal is I save your ass. That's enough charity."
Shaw later talks to Reid about how there is no upside to being a hero. Reid tells Shaw about the inmates making demands for him and Luis, and remarks that they are willing to negotiate. Shaw replies that he might be willing to do some shuttle diplomacy. He asks Reid what he is offering to the inmates, and Reid replies that he will do anything that isn't illegal. Later on, Shaw is visited by Alvez and guesses that he is checking on Reid to see if he is okay. However, Alvez says that he was visiting Shaw only and refers to him by his first name. Alvez proceeds to explain everything he learned about Shaw during his training classes, and deduces the reason why he turned himself in: his son. Then, Alvez threatens that if Reid is hurt in prison again, he will make Shaw suffer and take away his son. Shaw leaves the visitors' area afterward.
The next day, while he is playing chess with another inmate, Shaw is approached by Reid, who forces the other inmate to leave. They talk about Reid's safety, and Reid tells Shaw that he wants his protective measures extended to Luis as well. Shaw refuses, saying that protecting Reid was "enough charity" from him. Reid tells him about his plan to go to the prison guards and offer his cell to Luis, since the other inmates can't touch him there. This frustrates Shaw and he leaves.
During visiting hours, Shaw witnesses Reid being visited by Rossi. When a sudden lockdown occurs in Millburn, he asks Officer Lionel Wilkins what is going on, and is informed about a tip that turned up a secret shipment of drugs. Shaw is next seen in his cell playing chess with Reid again and asks him if Rossi was the one who came to see him; Reid affirms it. He asks him if he taught Reid a chess move that he had just used. Reid replies that it was Gideon, his mentor who was killed a couple of years ago. Shaw tells Reid that he needs to move on from Luis's death. Reid asks Shaw if he knew Frazier and Duerson would kill him; Shaw replies that he believed they were going to send a message, but thought that it wouldn't be that loud.
The next day, Reid and Shaw play another game of chess. Then, Reid asks Shaw how he knows Malcolm, another inmate who became his new partner in the laundry room, but Shaw denies knowing him. Reid tells Shaw that he is not going to move Frazier and Duerson's new shipment of drugs, but Shaw warns him that the inmates are going to beat him again. Reid replies that he will survive, then tells Shaw about his belief that he is the one pulling the strings in prison, and the one who decides when to help and when to look away, citing the fact that Shaw seems to have a lot of friends on the inside. Unfazed by the assumption, Shaw tells Reid that he is losing his mind. At the end of the episode, Shaw is seen in his cell, coughing severely and bleeding. It is revealed that Frazier and Duerson had distributed the newest drug shipment throughout Millburn, but not after Reid spiked the drugs with a poison.
After fully recovering from the poison, Shaw, having realized who spiked the drugs, informed the other inmates about Reid's former status as a federal agent. He and a few other inmates later watch as Reid talks with Malcolm, who later leaves him after realizing he was an agent. Later, Shaw sits with Reid and tells him that he needs to grow some eyes in the back of his head, since he will never see another attack coming. Then, Reid tells Shaw that he has a better idea and tricks Shaw into stabbing him in the leg with a shiv. This causes a riot, and the guards take Reid to solitary confinement while Shaw is thrown back into his cell.
Eventually, Shaw sends Reid a letter containing an implicit threat towards him, which causes Reid to worry if he truly is safe in solitary confinement. However, the next day, Reid is released from prison due to new evidence coming to light. Immediately afterwards, Shaw talks to Alvez, telling him that he doesn't know who he is messing with. Alvez tauntingly replies that he does. Then, Alvez tells Shaw that he arranged for his transfer to another prison in Michigan, adding that he will not see his son as much anymore and that the inmates (members of the Russian Mafia who Shaw put away during his time as an agent) are excited to see him.
Given that Shaw only killed one victim, the term "M.O." may be misused. When he killed Elena Olegnova, he shot her numerous times with a handgun. He intentionally shot her at least once in her uterus to destroy any evidence of the child he had conceived with her.
In Green Light, it is implied that Shaw was planning to orchestrate an attempt on Reid's life, having informed the other inmates about Reid's status as a federal agent and telling him that he needed to "grow eyes on the back of [his] head". He later unintentionally stabbed Reid in the leg with a shiv, though it was a ploy conceived by Reid who had placed the weapon in Shaw's hand.
Shaw was never officially profiled by the BAU, but Alvez was able to deduce the real reason he killed Elena Olegnova by studying the way she was killed. Later, in Green Light, Alvez theorized, based on Shaw's personal belongings in his cell, that he was a sergeant in the cartel operating inside Millburn, who was well rewarded for his ability to accomplish his tasks.
- Unspecified date in 2005: Elena Olegnova (his confidential informant and lover; shot repeatedly, including once in the uterus; was pregnant with his child)
- April 15-16, 2017: Spencer Reid (indirectly attempted; manipulated into non-fatally stabbing him in the leg with a shiv)
- For reasons unknown, the guest cast for Alpha Male credits him as "Smitty", even though he was referred to as Calvin Shaw throughout the entire episode and in following episodes. The guest cast for Assistance Is Futile fixes this.