Grandma Gertie (or otherwise known as “Pookie” by Phil) is Arnold‘s paternal grandmother. She is wife of Grandpa Phil, and they have known each other since childhood. They had a relationship like Arnold and Helga when they were young. Gertie was mean to Phil (although in more extreme ways, like putting thumbtacks in his seat, dunking a part of her hair in ink and telling the teacher, Mrs. Crenshaw, that Phil did it, etc.). Grandma Gertrude runs a boarding house with Phil, they are the parents of Arnold’s dad, Miles, and they also have another son. Most of the boarders think she is crazy, because in every episode, she has a different theme that can be seen in her clothes, the way she talks, and the food she prepares for the boarders. The one time she’s “sane” is when everyone else is going insane during a heat wave.
She often is used as a philosophical source, especially with Arnold, through the use of metaphors that are usually not understood.
Grandma was a prominent character in the first season, but as the series went on she appeared less and episodes did not focus on her.
Gertrude usually acts younger than she appears. She is a martial arts master according to Gerald. She taught Arnold self-defense in “Mugged” episode and helped him save a turtle from the constant torment from the elementary school children in “Field Trip” episode. She is often the only person who understands Arnold. She is very upbeat, and takes any situation with the same enthusiasm as any other. This was best shown in “The List,” where Arnold failed attempts at having “the perfect Saturday” are compared with Grandma Gertie’s attempts to get her piano moved into the house. In the end, she has the piano put on the roof (where it stays for the rest of the show), and she and Arnold share a song about how you shouldn’t let the little problems get you down.
She has a habit of mixing up holidays in holiday episodes of the show. For example, during Arnold’s Christmas, she says “Happy Thanksgiving everybody!” She plays the piano; and during holiday episodes, plays seasonal music, but confuses it; she played Christmas music in the Thanksgiving episode.
Examples of Grandma Gertie’s wacky outfits and acts include the following:
24 Hours To Live, Abner Come Home, April Fool’s Day, Arnold, Arnold’s Christmas, Arnold’s Halloween, Arnold’s Hat, Arnold’s Thanksgiving, Back to School, Big Caesar, Casa Paradiso, Das Subway, Family Man, Field Trip, Fighting Families, Friday the 13th, Gerald Comes Over, Girl Trouble, Grandpa’s Birthday, Grandpa’s Packard, Grandpa’s Sister, Heat, Helga Blabs It All, Helga Sleepwalks, Helga’s Locket, Hey Arnold!: The Movie, Mugged, Operation Ruthless, Oskar Gets a Job, Parents Day, Partners, Rhonda Goes Broke, Save The Tree, Snow, Spelling Bee, Summer Love, The Baseball, The Journal, The List, The Old Building, The Vacant Lot