He seems to have displayed similar mischievous, possessive and selfish tendencies to Greg in his childhood, as in Old School, it is revealed that as a child he invented the mythical cryptid Silas Scratch to keep others away from the maintenance shed with a working bathroom at Hardscrabble Farms which he snuck into and used for his convenience.
Frank is depicted to be addicted to junk food; in The Last Straw, the character makes a New Year's Resolution to go on a strict diet, but Greg later catches him in the garage eating brownies.
However, he shows affection to him in the Diary of a Wimpy Kid: Dog Days film when Rodrick is allowed to bring his band, "Löded Diper", to celebrate his crush's (Heather Hills') 16th birthday.
He has shown cases of unusually high intelligence; for example, switching all his family's power to his room in Cabin Fever during a blizzard, resulting in Greg, Rodrick, and Susan almost freezing to death in the ensuing chaos (excluding Frank, as he was in a hotel at the time), and speaking fluent Spanish to two repairmen in “Diary of a Wimpy Kid: The Long Haul”.
Until Old School, he lived in a retirement community called Leisure Towers and enjoys playing games such as "Gutbusters" and Rummy, which the two boys find boring.
In the book, he marries his fourth wife, Sonja, although in a speech at the wedding it is revealed that Gary had hoped to end his relationship with her to date her sister, however when the couple were attending a basketball game, a plane flies past with a banner attached to it reading "Marry Me Sonja," presumably intended for another woman with the same name, yet Gary's partner assumes the banner refers to her.
In Hot Mess, Gary unexpectedly joins the Heffleys' trip to Ruttyneck Island, after losing his job at Skullduggery Cove, which was being rebranded as a butterfly sanctuary.
She appears in Hard Luck multiple times via video conference and in person in Hot Mess, where it is revealed that she owns a celebrity dog named Dazzle, who became a social media star after constantly appearing in her videos about money investments, forcing her to move twice after constantly getting free stuff and people showing up at her house to see Dazzle.
He was adopted by Great Aunt Marcie, and Greg often feels awkward around Cecil, due to the fact that he gets privileges (such as sitting at the adult's table at family gatherings), despite his young age.
This earned him the respect of many other kids and allowed him to win the "Most Popular" class favorite category in the yearbook, where he shows he can also blow a bubble.
Holly makes a cameo in The Ugly Truth talking to some of her friends, and this is her most recent appearance in the books, though she was shown in a chart Greg drew in The Third Wheel as one of the many girls interested in Bryce Anderson.
Whereas her personality is hardly explored in the books, Holly's role was increased in film adaptations, debuting in Diary of a Wimpy Kid: Rodrick Rules as a newcomer to Greg's school with whom he is instantly besotted.
Holly seems to enjoy the boys' companionship and shows gratitude for Rodrick's unintentional blunders that wind up destroying her sister Heather's birthday party.
Motivated by his lust for revenge to pay back on her, he volunteers to play a tree in the school's upcoming production of The Wizard of Oz after viewing the movie adaptation for the first time.
He believes the role entails having to bombard the character of Dorothy Gale (whom Patty would be portraying in the play) with apples, only to learn that this scene was deleted for the school production.
Albert has appeared in The Last Straw, The Ugly Truth, Old School, Double Down, The Meltdown, Wrecking Ball, The Deep End, Big Shot, and No Brainer, and was briefly mentioned by Greg in Hot Mess.
Bryce has appeared or been mentioned in Diary of a Wimpy Kid, The Last Straw, The Ugly Truth, Cabin Fever, The Third Wheel, and Hard Luck.
Their main camp consists of several abandoned cars and trucks deep in the woods, which had remained unknown to the town until Greg and Rowley accidentally discovered it in The Meltdown.
They have been shown to wake up early during the winter when they are disturbed and will go to great lengths to get back at an insult (Greg infiltrating the camp and accidentally stealing Meckley's belt buckle).
Their most recent appearance was in The Ugly Truth when they move to another house because of a strange smell they cannot get rid of in their home following another half-birthday party for an unnamed child.
In Cabin Fever, their vacant house is moved into by a man called Mr. Alexander, who has uneven teeth that Greg's dad thought were fake the first time they met.
Like Hall in the book, Müller was the last victim of the Cheese Touch and fails to pass it on, eventually taking it with him when he and his family move back to Düsseldorf.
During one of Susan's games where one had to tell everybody something about oneself when one had the ball, Edward finally started talking about how his stepmother is so strict and how she does not like the pet turtle he got for his birthday.
But on the bus, Greg discovers that the poem is written in Rodrick's handwriting and has numerous inconsistencies with the time period and history as a whole (including references to cave people and dinosaurs).
Greg and his family are convinced that the Beardos have stolen their luggage and belongings at Soak Central after they steal their pool chair and they find their supposed locker empty.
Greg at first considers telling the other students that Silas Scratch is a hoax but decided not to, as he figures that he might be stuck chaperoning at the farm when he is older, and he will want to use the shed as well.
Before the band broke up, people kept telling Stew that he was the "real star of Metallichihuahua", resulting in him creating a solo holiday album, which totally flopped (according to Greg).
After Rodrick gets a cease and desist letter from a trading card company, Drew, Bill, and Mackie leave the band (they did not want to risk going into an expensive legal fight).
In Diary of an Awesome Friendly Kid, Rowley goes outside and tells her to call the cops on a burglar, only to find out that it actually was Greg playing a prank on him.
After causing havoc in a hotel room, and nearly leaping onto a busy highway, the Heffleys decide to get rid of the pig by donating it to a petting zoo, much to Manny's dismay.