|“||I think your heart... is more pure than you know.||„|
|~ To Helga|
Arnold's head is shaped like an American football, thus earning him the nickname "Football Head". He is usually seen wearing his favorite blue hat and an oversized red plaid button up underneath a teal sweater. In the pilot, his sweater is orange and his undershirt is blue.
Arnold is kind, caring, brave, calm, peaceful, self-less, smart, and wise. Arnold often daydreams and has had a wild imagination, this has been a trait since the character's conception. He is very forgiving and sympathetic towards Helga, despite her constant harassment of him to hide her true feelings. Throughout the series, he is completely unaware of Helga's feelings for him, other than the occasional hint from Helga and other classmates. Arnold also likes listening to Jazz.
Arnold Shortman was born and raised in the fictional city of Hillwood. He lives at the Sunset Arms boarding house with his Grandpa Phil and Grandma Gertie, as well as four other boarders who rent. Arnold's room is located in the attic which has been converted into a bedroom. When Arnold was a baby he was left with his grandparents while his parents went off on a mysterious trip to San Lorenzo; Sadly they never returned. Despite the tragic loss of his parents, Arnold is very strong willed and is always willing to help others that are in need. Arnold also has a pet pig named Abner who he cares for a lot.
Hey Arnold!: The Movie
In Hey Arnold!: The Movie, a greedy developer named Scheck plans to tear down Arnold's neighborhood and in it's place build a huge "mall-plex". Arnold and Gerald undertake a huge mission to recover an incriminating document and ultimately save the neighborhood.
Hey Arnold: The Jungle Movie
In Hey Arnold!: The Jungle Movie, Arnold and his best friend Gerald plan to make a humanitarian video during the summer, after their fifth grade year to win a trip to San Lorenzo. This is where Arnold's parents were last seen, as mentioned in the final episode of the series The Journal.
They try to record themselves making a home out of junk for one of their friends, eccentric Monkeyman, but that backfires; Arnold leaves, heartbroken. Arnold's teacher Mr. Simmons reveals to everyone that Arnold's video won the competition and he, his classmates of P.S. 118, and Helga's older sister, Olga, fly to San Lorenzo.
While on the plane, Arnold's pet pig Abner stows away in his backpack. When everyone arrives in San Lorenzo, they are greeted by Arnold's parents' old friend, Eduardo. Aboard a ship, Eduardo privately warns Arnold of the jungle's dangers and gives him an amulet said to lead them to the "Green-Eyed People", the residents of San Lorenzo's lost city. Later that night, Helga tries to confess her feelings to Arnold, but the boat is attacked by pirates. After learning the secret that Arnold kept from them, Gerald and the others shun him.
When the group reaches a base camp, "Eduardo" reveals himself to be a mercenary named Lasombra, who disguised himself as Eduardo to deceive Arnold and the others. He and his men imprison everyone, explaining that the contest was a trick to lure Arnold to San Lorenzo so he could use him to find the lost city and its treasures. Helga and Gerald manage to escape and free Arnold, and use Arnold's father's old journal to find the city; unbeknownst to them, Lasombra anticipated this and placed a tracking device on Arnold's green eyed necklace. Arnold and his friends manage to evade the lost city's traps.
Arnold and the others reach the city, finding it populated by children due to a "sleeping sickness" that has left its adult population comatose for nine years. The group finds a statue said to contain the Corazón, a treasure that may lead to a cure for the sickness. Lasombra corners them, taking Arnold hostage and stealing the statue. While Gerald and Helga give chase, Lasombra forces Arnold to open the statue using the amulet. When Lasombra tries to take the Corazón within, the statue's defense system shoots him in the forehead with a poisoned dart, sending Lasombra over a cliff.
A mysterious man arrives in to save them and reveals himself to be the real Eduardo, who explains to them that the pirate "attacking" them earlier was him trying to rescue the group from Lasombra. Lasombra climbs back up from the cliff and gets into a brief scuffle with Eduardo, knocking the Corazón off the cliff, before succumbing to the poison and plummeting to his death. The group returns to the city, and Arnold finally sees his parents, Miles and Stella, who have also contracted the sleeping sickness. Without the Corazón to release the cure to the infected population, Helga uses her locket containing a photo of Arnold as a replacement. The temple releases the cure and the infected are revived. Arnold and the city's children reunite with their parents. Arnold thanks Helga for her loyalty and finally realizes the depths of her feelings for him, and the two share a kiss.
A few months later, life as normal has resumed at Arnold's grandparents' boarding house, though now with Miles and Stella living there as well. Arnold says goodbye to his parents as he heads off for his first day of sixth grade with Gerald, Phoebe, and Helga. Gerald and Phoebe are seen holding hands walking to school together, while Arnold and Helga are also implied to be a couple despite Helga pretending to remain hostile towards Arnold once in public. Arnold's parents walk with him and his friends to school and Arnold promises his mom and dad that they'll see him at 3:30 as the doors close behind him.
It's also implied at the end of the movie that he and Helga become a couple, as Arnold holds hands with Helga (although Helga pretends to be hostile to Arnold in public).
- According from Hey Arnold's creator, Craig Barlett himself; Arnold and Helga do get married and have children.
- While his surname is never revealed in the show, it was confirmed to be Shortman by Craig Bartlett in an interview with BuzzFeed (and talked about in The Jungle Movie), it was also hinted in the show by his Grandfather.
- Throughout the entire series and up to The Jungle Movie, Arnold has been a true hero in his own neighborhood by helping and reasoning with his friends and loved ones in solving their problems they've been facing and other things as well. Ironically, he is very similar to Samurai Jack.
- Throughout the series' run, he was voiced by at least five different voice actors:
- J.D. Daniels (who did his voice in the pilot)
- Toran Caudell (who was also the voice of the bully Wolfgang)
- Phillip Van Dyke
- Spencer Klein (who did his voice in the movie), and
- Alex D. Linz who did April Fool's Day and The Journal.
- Mason Vale Cotton (who did his voice in the second movie)