On the morning of November 7, Callahan and Powell were playing cards when Police Chief Jim Hopper arrived late for work. Callahan jokingly mocked his appearance, saying that he “looked like Hell.”
Callahan accompanied Hopper to Hawkins Middle School where they questioned Mike, Lucas, and Dustin about Will's disappearance. When Mike mentioned Mirkwood, Hopper asked Callahan if he had ever heard of it, to which he responded that it seemed made up. The boys then informed them that it was where Cornwallis and Kerley met.
Hopper and Callahan, along with officer Powell, began searching on Mirkwood. During their search, Hopper came across Will's bike. Callahan wondered if Will had possibly fallen off his bike and gotten hurt, but Hopper thought this as odd, saying he would've walked his bike home instead of leaving it there. The three officers brought the bike back to the Byers' and searched the house for any signs that Will had managed to get home the night he disappeared. As Hopper became preoccupied while inspecting the shed, Callahan finally managed to get his attention. Hopper then urged Callahan to call Flo in order to organize a search party.
While attending the search party, Hopper briefly met with Callahan and Powell to discuss if they had found anything. After Hopper had walked ahead, Callahan inquired if Hopper had once had a sexual relationship with Joyce, but Powell ignored him.
The officers continued their search at the quarry. As Callahan stood next to the cliff's edge, Hopper advised him to back away. Callahan said he could make the jump, recounting how George Burness had survived while drunk for a bet. Hopper warned that the fall would kill him, but Callahan remained unconvinced. Hopper then received a call from Flo telling him to head over to Benny's. After arriving at the diner, the officers found Benny's corpse, arranged to look like a suicide. The discovery, along with the case of the missing Will Byers, made Callahan remark that Hopper must “feel like a big city cop again”.
Callahan was present when Hopper questioned Earl about Benny. When Earl mentioned that a “boy” with a shaven head tried to steal food from Benny, Callahan presented him a copy of Will's missing poster. Hopper wondered if the kid Earl witnessed was possibly Will with a buzz cut. Initially, Earl was unable to give him a certain answer, but he eventually concluded that the kid could have been Will. That night, as Callahan, Powell, and Hopper took part in the search party, Callahan wondered the validity of Earl's statement. Their attention was suddenly drawn to Scott Clarke, who had found a piece of ripped cloth at the edge of the drain pipe. The pipe led to Hawkins National Laboratory, making the officers suspicious of the lab.
The next day, the three officers decided to visit the lab, but were initially denied entry by the security guard. However, Hopper convinced him to let them enter the premises. They were then escorted by the Hawkins head of security, who dismissed their claims. He insisted that they would've known if a kid had managed to sneak into the lab due to the cameras and tight security. Hopper then requested to see the security camera footage from the night of the 6th and 7th. Fulfilling his request, the head of security led the officers into the lab allowing them to view the footage, but there was no sign of Will. As the officers were leaving, Hopper realized there was no rain present in the footage, making him even more suspicious of the lab.
Callahan was present at the scene when what was assumed to be the body of Will Byers was retrieved from the quarry. He then accompanied Hopper and Powell to the Byers' house where he briefly spoke with Joyce and Jonathan.
At the high school, Callahan and Powell questioned Nancy about the night Barbara Holland disappeared. Nancy believed that a strange creature she saw may have taken Barb, urging the officers to go and investigate Steve's house. Callahan informed her that they had already searched the residence and found nothing--not even Barb's car. The officers believed that Barb had possibly ran away due to jealousy, but Nancy insisted Barb would never do that though they didn't believe her.
Being unable to contact him, both Callahan and Powell visited Hopper at his trailer. While there, they informed him that Bev Mooney was worried about Dale and Henry, who had not returned from their hunting trip. They also told him that state police had found Barbara Holland's car parked at a bus station, making them believe that she had ran away.
Following a theft at Bradley's Big Buy, Callahan and Powell were called to the store by the manager. They took statements from the manager, as well as a clerk, who described the shoplifter's appearance to the officers.
As Jonathan and Steve fought in an alleyway, Callahan and Powell arrived on the scene. While trying to restrain them, Callahan was unintentionally hit in the face by Jonathan. As Powell arrested Jonathan, Callahan pursued Steve and his friends but was unable to apprehend them.
Callahan notified Hopper of Jonathan's arrest, summoning both him and Joyce to the police station. When they arrived, they urged Callahan to remove Jonathan's handcuffs. Callahan refused, stating the reason he was wearing them was because he had assaulted a police officer. Both he and Powell then revealed the stash of “monster hunting” supplies in the trunk of Jonathan's car. Hopper demanded to know why he had such items, but Jonathan said he wouldn't believe him.
As Hopper spoke with Jonathan and Nancy in his office, a woman came to the station in order to report that her son's arm had been broken by a “psychotic child.” As Callahan and Powell questioned her, they got into an argument, with her believing that they were humiliating her son. She demanded an apology and to speak with the chief. Callahan argued to Hopper that he was just trying to state facts, but Hopper told the officers to take a statement. When Troy described the girl's appearance, Hopper took interest and asked for more information. He then explained the girl's telekinetic abilities, and that she was with Mike, Lucas, and Dustin.
On Christmas Eve, Callahan attended the Christmas party held at the police station.
Officer Callahan now sports a freshly grown "police style" mustache. When journalist Murray came to the police station to convince Hopper his claim of the presence of a Russian spy in Hawkins, Callahan laughed away and trifled his theory. He and Calvin Powell assist Jim Hopper during the investigation of the pumpkin fields early on in the season's story arc.
On July 1, 1985, Callahan is present when an ambulance takes Doris Driscoll as she was found consuming fertilizer, as she screams frantically. Creeped out by the scene, Callahan asked Nancy and Jonathan, who had found the elderly lady in this state, what was the significance behind it all.
The next day, Callahan went to the Hawkins Post and spoke to the Chief editor Tom Holloway (who had become flayed) about the matter and left before Tom called Nancy and Jonathan into his office and fired them.
Callahan was gullible, easily believing George Burness had survived his jump into the quarry, as well as the rumors of Hawkins Lab building “space lasers”. He also had a habit of overstepping personal boundaries, especially when it came to personal relationships. He once asked Powell if Hopper and Joyce had ever had a sexual relationship, and later when he was questioning Nancy about her relationship with Steve, he insinuated that they had done more than “just talk”.
|Season One appearances|
|The Vanishing of Will Byers||The Weirdo on Maple Street||Holly, Jolly||The Body|
|The Flea and the Acrobat||The Monster||The Bathtub||The Upside Down|
|Season Two appearances|
|MADMAX||Trick or Treat, Freak||The Pollywog|
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|Season Three appearances|
| || ||The Sauna Test|
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