Frank Heffley

Frank Heffley is Greg's, Rodrick's, and Manny's father. He is the husband of Susan Heffley (Greg's mom).

Frank is a recurring character that respects self-discipline, honesty, and exercise - as a result, he shuns video games and Rodrick's friends. He is always trying to get his sons to exercise much in the manner of his boss, whose has three sons that are about Greg's, Rodrick's, and Manny's age, and are sports fanatics.

In the third book, Diary of a Wimpy Kid: The Last Straw, Frank gets fed up with Greg's behavior and threatens to send his son to Spag Union Military Academy to toughen him up, because the academy turned Lenwood Heath, a prankster, into a polite young man. Greg tries to circumvent this by proving to his dad that he does not deserve this treatment by "doing his best" in soccer and joining the Boy Scouts, among other things, but ultimately fails. It is not until Seth Snella's half-birthday party that Frank realizes that his son's wimpiness is a good thing, because it saved himself from looking foolish in front of the entire town.

In Diary of a Wimpy Kid: Dog Days, Frank has a rather minor role in the story until Father's Day, where Grandpa admits that he lied to him about his dog, Nutty, running off to a "butterfly farm", and instead admitted that he accidentally killed his dog. Frank, in response, becomes furious, and decides to buy another dog to make up for the lost one. This dog was named "Sweetheart" much to the three siblings' dismay, or Sweetie for short. Frank becomes obsessed with this dog, even though Sweetie is two times as lazy and repulsive as Greg.