The sheriff (who is unnamed) became a werewolf a week prior to the episode's events, when Old Man Chaney's dog (which is really a wolf) bit his left hand. In his first appearance in the episode, the Sheriff arrests Reggie for his prank which involved him dressed as a werewolf when there's a real one out on the loose all over Riverdale. However, the Sheriff turned heel later that night when he transformed into a werewolf and went after Archie, who was out with Betty, Veronica, and Jughead. The werewolf chases Archie, who later traps him in the restroom. After breaking out, Archie barely escapes in his car. Fully unaware of his lycanthropic nature, the Sheriff agrees to take in Reggie after he believes that he is the werewolf.
While in jail, Reggie asks the Sheriff about his hand, to which he explains about how he was bitten by Chaney's "dog." He also reveals that he had Reggie's letterman's jacket (which he had on in his werewolf form) and was looking to return it, but he couldn't remember what happened next. It was at that moment that the full moon appeared and revealed the Sheriff's heel persona, as he turned into a werewolf and went after Reggie. Archie and Jughead enter the station, where they encounter the werewolf Sheriff, and it is at that moment that Archie places his silver necklace around the Sheriff's neck, which caused him to revert back to his human form. After learning that he is a werewolf, the Sheriff thanks Archie for the necklace, stating that he'll keep it on always.