Hey Arnold! is a much-loved and popular Nicktoon on Nickelodeon. The whole basis of the show is Helga's love for Arnold, but a lot of episodes and storylines focus on Arnold and his friends. Hey Arnold! shows a variety of different characters - even the background characters have 1 or 2 episodes on themselves. Arnold is a good person and tries to do things right. People at his school seek him for advice and see him as their own advisor.
Arnold - Arnold is the main character of Hey Arnold!, Arnold is very helpful to others but gets too much into their business sometimes. Helga loves Arnold more than anyone else. But Arnold doesnt know it. Arnold's last name isn't revealed in any episode, but will be in the 2004 sequel, Hey Arnold 2! Arnold's nickname is "Football Head".
Gerald - Gerald is Arnold's cool best friend and the all-time keeper for the ancient legends of Arnold's neighborhood.
Helga - Helga is the meanest kid in Arnold's neighborhood for one reason - she loves Arnold! And no one else knows that! Helga's best friend and sidekick is Phoebe.
Harold - Harold is big and fat bully, and could swallow 50 Mr. Fudgie-bars whole! He's mostly hanging out with Stinky or Sid. Harold also thinks hes so tough but he always cries for his mommie.
Phoebe - Phoebe is the Smartie! She's very useful when Helga needs help with something... or needs her to do Helga's homework. Phoebe loves Gerald, so does Gerald but its hard to tell what's gonna happen. Phoebe also knows Helga's big-deep-dark secret about Arnold, but is positive she won't let it out.
Rhonda - Rhonda is the rich/cool girl. She's always depending on people to have a good fashion scene, though it never works. Rhonda is best friends with Nadine. Nadine likes everything the opposite of Rhonda and so does Rhonda but they still work out their fights.
Stinky - Though his name is Stinky, he's really not. This farm-yard boy is taller than any other and is always sharing his love about lemon puddin'.
Sid - Sid is always pessimistic about everything. He is very gullible and will believe anything anyone says. He's best friends with Stinky and Harold.
Eugene - Eugene is the clutz! Whether he turns a good day into a nasty storm, he's very optimistic about everything. He's also known as a geek to many others.
Grandpa and Grandma (Phil and Pookie) - Arnold's "substitute parents" are the craziest, most loving "substitute Parents" a kid could want! They're also Arnold's grandparents.
Oskar - Oskar is a resident of the boarding house that Arnold lives in. He loves money (but relies on his wife Susie for it), he can be very lazy at times.
Susie - Susie is Oskar's wife. She mainly does all the cooking, cleaning, and works since Oskar has only a paper route, and can be irratted by that sometimes.
Ernie - Ernie also lives in the boarding house and is a construction worker. His room his filled with blocks, each telling a story. Ernie is very short, but has a very big heart.
Mr. Hyunh - Mr. Hyunh is an asian man who came to the boarding house from China during Vietnam. He has a daughter and also a very good voice.
Mr. Green - Mr. Green owns the meat shop called "Green Meats". He's always there to help, and sell meat of course.
Curly - Curly is the cookoo one. He's always crazy like one time he locked himself in the principle's office and threw dodgeballs at people. Crazy, huh?
Ms. Vitello - Ms. Vitello is the very old, nice, and tender owner of the flower shop on Arnold's block.
Big Bob (Helgas Father) - Big Bob owns a beeper shop called Big Bobs Beepers. He is a bossy meanie(where Helga gets it from).
Arnold's Mom and Dad - From the episodes "Parents Day" and "The Journal", Arnold's parents write in a journal about all the adventures they had in the wild, saving people's lives and then having Arnold. From what everyone knows, they've never came back to where they went.