Greg's grandfather is an outgoing person, and he is shown to wear a tie (shown in The Ugly Truth). He tends to baby Greg in some ways such as, reading him bedtime stories and watching 30 minutes of television. Greg has said in his journal that his grandfather has not babysat them in years. In Dog Days, it is revealed over Father's Day brunch he ran over his son's dog Nutty when backing out of the drive way. He is a smoker and enjoys playing gin rummy.He drives a dodge.
Grandpa appears in the second film and third film, Rodrick Rules and Dog Days.