Stanley (Stan) Marsh Male. 17 years old. Stanley (Stan) Marsh. He first is portrayed as "a normal, average, American, mixed-up kid. Stan is who commonly has extraordinary experiences not typical of conventional small-town life in his hometown of South Park. He acts as the de facto leader of his friend group, often encouraging them in difficult times and taking charge in social causes. Much like his best friend Kyle, Stan often learns a valuable lesson by the end of episodes. Stan has black hair, light skin, blue eyes. He usually wears a navy-blue beanie cap with a red trimming and a red pom-pom ball on the top of it, matching red gloves, a light-brown jacket with a matching red collar, blue jeans, and black shoes.

Kyle Broflovski Male. 17 years old. He often displays the highest moral standard of all the boys and is usually depicted as the most intelligent. When describing Kyle, states that he are "reactionary", and susceptible to irritability and impatience. In some instances, Kyle is the only child in his class to not initially indulge in a fad or fall victim to a ploy. This has resulted in both his eagerness to fit in, and his resentment and frustration. Kyle is distinctive as one of the few Jewish children, and because of this, he often feels like an outsider amongst the core group. Kyle has curly red hair, a light skin tone, eyes green. He wears a bright-green ushanka hat (ear-flap hat), matching green gloves, an orange coat with a matching green collar, army green cargo pants, and black shoes.

Kenneth (Kenny) McCormick Male. 17 years old. Kenneth (Kenny) McCormick. He is friends with Stan and Kyle, while maintaining a friendship with Eric Cartman. Kenny died in almost every day, with only a few exceptions. The nature of the deaths was often gruesome and portrayed in a comically absurd fashion, and usually followed by Stan and Kyle respectively yelling "Oh my God! They killed Kenny! You bastards!" Kenny canonically has an ability to resurrect after dying, though he is always the only one who can ever remember dying, despite his friends always bearing witness. Kenny has bright-blond hair, a light skin color, blue eyes. He wears a large orange parka whose large hood conceals his blond head completely with a faded-brown inside, matching faded-brown gloves, orange pants that match his parka, and black shoes. Kenny has a brother named Kevin, and a younger sister named Karen with whom he has a good relationship.

Eric Theodore Cartman Male. 17 years old. Among main child characters, Cartman is distinguished as "the fat kid," for which he is continuously insulted and ridiculed. He often makes antisemitic insults towards Kyle for being Jewish, constantly teases Kenny for being poor, particularly manipulates and mistreats Butters Stotch. He has short straight neatly-parted brown hair, pale skin, eyes blue, and an extremely fat body with neck flab and a double chin. Cartman wears a small teal hat with a small flat yellow puff-ball on top and a matching yellow band where the forehead part of the hat begins, a large bright-red coat, matching yellow gloves, brown khaki pants, and black shoes.

Craig Tucker Male. 17 years old. Craig, commonly characterized by his blue aviator or chullo hat and deep nasal monotone voice, is one of the more prominent members of the children's classroom. In the first, Craig has a habit of giving people the finger, a trait attributes to his learning the behavior from his family, all of whom frequently use the gesture as well. Despite his dislike of the main characters, particularly Cartman, he is often depicted as one of the boys who repeatedly join Cartman in his many schemes, at times serving as a right-hand man.

Tweek Tweak Male. 17 years old. Tweek is a fourth-grade student at South Park Elementary. He drinks lots of coffee, which is laced with methamphetamine, which causes him to be paranoid and have jittery muscle spasms. Tweek obviously has an anxiety disorder. As a character who is almost always under near constant anxiety, his catchphrase is either "Too much pressure!"

Leopold Stotch Male. 17 years old. Leopold (Butters) Stotch is a student of South Park Elementary. Butters is depicted as more naive, optimistic, and gullible than other child characters and can become increasingly anxious, especially when faced with the likelihood of being grounded, of which he is extremely terrified. As a result, he is often sheltered and unknowledgeable of some of the suggestive content his peers understand.

Tolkien Black  Male. 17 years old. Tolkien Black. He is the only black child in South Park until the introduction of Nichole Daniels. Originally named "Token", "Token Williams", and finally "Token Black" as a play on the notion of a token black character, his first name is actually "Tolkien" Tolkien addresses an assembly hosted by Stan in which he states that he hates his namesake, saying that he finds J.R.R. Tolkien's work to be "a bunch of nerdy, jive-ass dragon shit".

Wendy Testaburger Female. 17 years old. Wendy is most prominent female student. Her best friend is Bebe Stevens, she is the on-and-off girlfriend of Stan.

Bebe Stevens Female. 17 years old. The boys' blonde female classmate, Wendy's best friend, Clyde's on-again, off-again girlfriend, and the only child of Mr. and Mrs. Stevens.