thumb|300px|right|146 total instances of "Football Head" being used throughout the TV Series Football Head is Helga Pataki's favorite teasing nickname for Arnold given for the characteristic shape of his head. Wolfgang has a similar nickname for Arnold: "Football Face".
|“||I created Arnold when I first moved to LA, ten years ago [in 1988]. I was still doing clay animation on glass (the Penny cartoons from PeeWee's Playhouse) so I designed him out of clay. I cut out the football shape from a big sheet of clay, set the eyes wide apart, gave him the huge hair and tiny hat, and that was that.||”|
The oblong shape of the head is shared by Arnold's relatives: his mother Stella and cousin Arnie (which makes some think that he is Arnold's maternal cousin). His late maternal grandfather Arnold probably was football-headed as well. Ruth, though unrelated to Arnold, has oblong-shaped head as well.
Also Craig Bartlett mentioned, that "Football Head" is a popular motif in the architecture of the Green-Eyed people.
Helga even used an actual football to construct a secret shrine to Arnold.
"Football Head" in various translations
- Afrikaans: Voetbal Kop
- Chinese: 足球头 (Zúqiútóu)
- Czech: Šišatá hlava ("Pine Cone Head")
- Dutch: Rugbyhoofd ("Rugby Head")
- French: crâne d'oeuf ("Egg Head")
- German: Footballschädel ("Football Skull")
- Hungarian: Futballfejű (Football-headed)
- Japanese: フットボール頭 (Futtobōru Atama)
- Malay; Kepala sepak ("football Head") or kepala bola ragbi ("rugby ball head")
- Polish: Futbolowa głowa
- Portuguese (Brazil): Cabeça-de-bigorna ("Anvil Head")
- Portuguese (Portugal): Cabeça-de-melão ("Melon Head")
- Russian: Репоголовый (Repogolovyj, "Turnip Head")
- Spanish: Cabeza de balón ("Ball Head")
- Swedish: Fotbollshuvud ("Football Head")
- Turkish: Futbol topu kafanı
- Ukrainian: М'ячеголовий (Mjačeholovyj, "Ball Head")
- Greek: πατατοκέφαλος (potato head)