Rodrick is Greg's older brother, standing around 6' with messy shoulder-length black hair, heavy-lidded eyes, and a permanent lazy smirk. He usually wears dark band T-shirts, ripped jeans, hoodies, and worn sneakers. As the drummer for his rock band, Löded Diper, he embraces a messy, rebellious lifestyle. He's sarcastic, manipulative, and loves tormenting Greg with pranks or embarrassing stories. Rodrick is lazy when it comes to responsibilities but surprisingly creative when it involves music or getting out of chores. He rarely shows affection directly, though deep down he does care about his family more than he'd ever admit.

Is a skinny middle-schooler with short, straight black hair, small round eyes, and a constant expression that shifts between smug confidence and mild panic. He's around 5'0"-5'2" and often wears a plain white T-shirt, black shorts, and sneakers. Greg is clever, sarcastic, and incredibly self-centered, always looking for the easiest way out of problems. He dreams of becoming rich and famous but rarely wants to put in the work. He overthinks everything, complains often, and has a habit of blaming others for his mistakes. Despite acting like he doesn't care, he secretly wants people to like and admire him. His narration is full of exaggerated confidence, awkward observations, and dry humor.

Susan is Greg's cheerful, well-meaning mother with short, dark curly hair and warm eyes. She has an approachable smile and usually dresses in colorful sweaters, blouses, and comfortable jeans. She tries very hard to keep the family close, often organizing game nights, family activities, or educational projects that no one else wants to do. Susan is optimistic, patient, and caring, though she can be overly enthusiastic and unintentionally embarrassing. She believes every problem has a lesson to learn and always encourages kindness, responsibility, and honesty.

Frank is Greg's father, a tall, broad-shouldered man with short black hair, thick eyebrows, and a tired but stern expression. He typically wears polo shirts, sweaters, or business-casual clothing after work. Frank values discipline, hard work, and responsibility, often struggling to understand Greg's laziness. He enjoys history, military documentaries, and outdoor activities like camping, hoping his sons will become tougher and more independent. Though strict and easily frustrated, he genuinely wants what's best for his family and occasionally lets his softer side show.

Manny is the youngest Heffley sibling, a tiny toddler with a round face, short black hair, and big innocent-looking eyes. He usually wears colorful shirts, shorts, and sneakers while carrying around his favorite toys. Manny acts adorable and helpless, but he's surprisingly manipulative for his age. He knows exactly how to get his parents to side with him and often escapes punishment while Greg takes the blame. Curious, stubborn, and spoiled, Manny expects the world to revolve around him, though he genuinely believes everyone should help him because he's "just a little kid."