Peter is a mature, well-mannered oldest child who was displaced by the arrival of his raucous younger brother, Fudge. The toddler is a constant source of annoyance to Peter; he “messes up everything he sees” and reacts to frustration by throwing himself “flat on the floor and he screams” (6). Obsessed with imitating his older sibling, Fudge destroys Peter’s school project and ultimately eats his sibling’s beloved pet turtle. Peter is happy when his father disciplines the child, noting, “For once my brother got what he deserved. And I was glad!” (28). Mrs. Hatcher, overwhelmed by the child’s antics, frequently coopts Peter’s help in cajoling Fudge into better behavior. For example, she begs Peter to entertain Fudge by standing on his head to encourage the toddler to eat.

Peter’s frustration with his mother is evident on a number of occasions. He wonders whether she cares about him at all when Fudge destroys his school project under her watch. When she inappropriately blames him for Fudge’s playground accident, Peter tells Dribble, “She doesn’t even like me” (39). Conversely, he accepts her subsequent heartfelt apology. When Fudge spends hours in the emergency room after eating Dribble, Peter reflects, “Maybe he wasn’t such a bad little guy after all” (116).