Billy Loomis is a supporting character and one of two villains in the original Scream film. He is the boyfriend of Sidney Prescott, the heroine of the film series. He is recruited into playing the part of Ghostface by Sidney's half-brother Roman Bridger. Billy is left susceptible to Roman's machinations due to his family being fractured by the Prescotts. Hank Loomis, Billy's father, was caught having an affair with Sidney's mother thus driving away his mother. Roman showed Billy the evidence of said affair and convinces him to aid in terrorizing and murdering Sidney Prescott. Billy is aided by his somewhat dimwitted friend, Stu Macher. Billy is killed when Sidney shoots him in the head.
Billy's mother was Mrs. Loomis, and his father was Hank Loomis. Hank was secretly in a relationship with Maureen Prescott, the mother of Billy's girlfriend Sidney. Billy was blissfully unaware. One day, Sidney's half-brother, Roman Bridger, approached Billy and showed him videos of Hank and Maureen, along with other men. Billy was infuriated. Roman suggsted that Billy kill Maureen, and gave him some pointers, such as getting an accomplice to sell out if he is caught.
Billy pressures his friend Stu Macher into being his accomplice. They are not caught, and want to continue their spree. Billy called Stu's ex-girlfriend Casey Becker on the phone; the call was at first charming, until he revealed that her boyfriend Steven Orth was tied to a chair outside. To defend Steve, Casey was forced to answer horror movie trivia (Billy was a horror fanatic). She got the second question wrong due to it being a trick question. Stu then killed Steve while Billy continued to taunt Casey over the phone. She refused to answer another question and hung up on him. Stu killed Casey and departed with Billy.
During a discussion in which Randy Meeks jokingly accused Stu of being the killer, Stu nervously denied it, and Billy immediatly shut Stu up. Their next target was Principal Hindry, who was stabbed by one of the killers in his office. By this time, the "Ghostface" costume had been identified, but nobody suspected Billy or Stu until a costumed Stu attacked Sidney in her house. Billy came to her defense, but he dropped his cell phone and she suspected him of making the calls. He was questioned, but the conclusion was that Billy was innocent.
Billy pretended to strain his relationship with Sidney in order to make her feel guilty for accusing him. She went to a party at Stu's house, which Billy and Stu had planned to be a bloodbath. Billy didn't show up at first but eventually invaded the house in the costume. He confronted Tatum Riley in the garage and she tried to run from him, but he ultimately sealed her doom when she tried to escape through a cat door. He raised the garage door, snapping Tatum's back. He then arrived as himself, and tossed Stu a look meaning that Tatum was dead.Billy asked Sidney what he could do to prove that he is not a killer moments before Stu came in and pretended to stab Billy. After an intense chase around the Macher house, Billy feigned injuries and fell down the stairs in front of Sidney. She handed him a pistol and he let Randy into the house. Quoting Norman Bates, he shot Randy in the chest and revealed himself as Ghostface. Sidney ran into the kitchen to hide from Billy, but Stu was waiting there, and revealed himself as Billy's accomplice.
Billy explained his motives and then held Sidney at "knifepoint" while Stu framed Sidney's father for the spree. Gale Weathers Riley then arrived and took the pistol from where Stu had set it down; she aimed it at Billy and Stu. Bily knocked her out and was about to shoot her, saying, "This is Gale Weathers, signing off..." until Stu noticed that Sidney had escaped. Sidney confronted them on the phone and Billy flew into a rage, ripping up pillows with the knife. Sidney then rammed him with an umbrella, causing him to fall down. She then killed Stu by dropping a TV on his head. Billy appeared, only to be shot in the chest by Gale.Randy warned Sidney that Billy would return for "one last scare". Billy then began to sit up, but Sidney shot him in the head, ending his life and Ghostface spree. Billy's mother would go on to become the second Ghostface.