Billy was the owner of Gizmo the Mogwai.
In the first film, he worked at the Kingston Falls bank along with Kate Beringer and in the second movie, he works at the Clamp Center building. Billy Peltzer began the first film as a humble bank worker in his hometown of Kingston Falls, a quiet, peaceful town. He is introduced as a shy, good-natured boy and a struggling young adult. His parents are Randall Peltzer and Lynn Peltzer. Randall, a struggling inventor, is the one who gave Gizmo, a mogwai, to Billy for a Christmas present. With this cuddly present came three rules: keep them away from bright light. Don't let them get wet. And most importantly; never, ever let them eat after midnight. Billy, for the time, followed all the rules quite adequately. Unfortunately, eventually the rules are broken, and a swarm of mischievious Gremlins are unleashed, turning this once-peaceful town into into a haven of chaos.
In Gremlins 2: The New Batch, Billy is living in New York City, along with his future wife, Kate the beautiful bank colleuge of Billy's. They work for multi-billionaire Daniel Clamp in his building, the Clamp Center; Billy in the design department and Kate as a tour guide. Billy soon discovers and saves Gizmo from the laboratory in the building where they work. Before he can take Gizmo home, Gizmo gets wet and spawns new mogwai even more deranged than the original batch. Billy, along with the help of old friends(and with the addition of some new ones), works to exterminate the gremlins before dark, and prevent them from terrorizing the town of New York, and the rest of the world. Good prevails, and after resolving the crisis, Billy is promoted by a thankful Clamp, and he and Kate take Gizmo home to live with them.
Behind the scenes
In both of the films, he was portrayed by actor Zach Galligan.