Clarence Francis "Kick" Buttowski is a 10-year-old boy and the main protagonist of the show. He aspires to be the world's greatest daredevil (his biggest addiction). He has an older brother named Brad and a younger sister named Brianna. His best friend is Gunther, a thrill seeking boy. His first appearance is in "Dead Man's Drop", the pilot. His catchphrases are "Aw, biscuits!" and "Chimichanga!"
Kick is a hard-headed, stubborn, self-tempered 10 year old who never backs down from a challenge. He always wears a stunt suit and a stunt helmet. His life's passion is extreme stunts. He is shown to have great determination, which occasionally clashes with his temperament. However, despite this all, he has been shown to have a kind heart, performing many kind acts. The damage to his surroundings which inevitably follows in his wake, is rarely intentional.
He has been shown to have quite a tolerance to pain, such as when he fell from space and into the earth's crust without even a single flinch. Though when Gunther has to pull a lot of thorns from his butt in "Dead Man's Drop", he yells out in pain. Brad calls him "shrimp", or any variation of the above, which generally angers him quickly. However, this is inconsistent, as seen in "Dead Man's Drop", where he takes all these comments without showing any change in emotion. He has been shown to have the ability to hold quite a grudge, shown in "Dead Man's Drop" when he yells 'You've made my revenge list Brad! Again!''then adding Brad's name to a list which contains only more times he has vowed to take revenge on his older brother.
Despite his bad grades and seeming inability to finish homework, he has also been shown to have a great ability to retain information. This is shown greatly in "Morning Rush!" when he has to do two months of homework in one night, which he does do, though Oskar eats it while he's showing Gunther. Then he manages to finish it all in less than six minutes and turns it in to Ms. Fitzpatrick and succeeds until Oskar appears again and eats his homework, implying that he'd been telling the truth when he claimed a dog ate it. Kick has shown to be skilled in many areas. The most demonstrated is his skill with various vehicles, with him (nearly) instantaneously gaining the ability to drive Billy Stumps' monster truck in "Stumped", as well as the abilities he has demonstrated with his skateboard, bike and cart. In some episodes, it is shown that Kick has skill in certain types of martial arts like karate, wrestling, boxing etc.
He is also shown to have engineering skill, as he is able to create a giant mechanical T-Rex with the ability to breathe fire in "Kickasaurus Wrecks". He appears to have a natural talent for anything that is "extreme", such as water skiing.
"I'm Kick Buttowski! And Kick Buttowski NEVER QUITS!"
Kick is stubborn and hard-headed but never quits a challenge. With his determination, strength, and smarts he usually succeeds. He naturally has no romantic feelings and just likes to have fun or destroy whatever is in his path. But in other episodes, he shows a nicer, cautious, and helpful side to himself too. He also speaks in a quiet but serious voice tone.
Kick always wears his white jumpsuit with a single red stripe on each arm with yellow boots and gloves. His helmet matches his jumpsuit. He is known to be un-naturally short and stubby for his age, so shopping can be hard for him. Kick almost never takes off his helmet, so very few (if anyone) have seen the top of his head.
Gunther and Kick display a typical inseparable type of friendship. It was revealed that Gunther and Kick have known each other since they were little in "Trike X-5". They have been known to have fights (as any friends do) but the biggest fight they have had so far was in "Abandon Friendship!", where they temporarily move on to new friends. However, they become friends again in the end. They've also drifted apart during "Obsession For Kick", in which Jackie Wackerman becomes enamored with Kick much to Gunther's displeasure.
Brad is Kick's older brother and his secondary antagonist. He will often to go out of his way to either cause problems for Kick, or interfere with his stunts. However, there have been occasions where (after a fashion) he helps Kick, such as the ending of "There Will Be Nachos", which has Brad use Kick's sudden fame to get his party running. Kick can also show care for his Brad, as seen when he helps his brother out in "Kart to Kart" and "Love Stinks!", to avoid humiliation.
"Wacky" Jackie (whom earns her nickname from her somewhat insane personality) is Kick's resident stalker. She appears to obsess over Kick in many ways, mainly for his daredevil nature. Gunther also has a crush on Jackie, which Kick uses to his advantage in "For The Love of Gunther", but this doesn't appear to last. Kick is mostly tolerant of Jackie for the most part, unless she interferes with one of his stunts. He has also helped her on occasion - "The Gift of Wacky" sees Kick throw her a birthday party upon realizing she has never had one.
Kendall is the polar opposite of Kick - where as he is into speed and daring, she tends to be collected and studious. Despite this, she is considered an antagonist to Kick, but the least threatening. They also seem to share a love/hate relationship, nearly kissing when forced to dance together in "Dancing With The Enemy"; however, they quickly revert back to normal. Additionally, she's the only person to refer to Kick as Clarence, his real first name on a regular basis. However, she's also been known to call him by his preferred nickname: "Kick" in the heat of the moment.
Kick actually likes Kendall at times as her inner awesome tomboy personality as prior in "Hand in Hand" when they worked together to get their hands stuck together from the sap in Ronaldo's garage. Once they got their hands stuck together they admitted they enjoy their time together and was about to go further as to a confession until Ronaldo came in unexpected.
In the episode "Rocked", Kick dreams himself played Rock Callahan, and Kendall is dreamed as beautiful, action-packed and pretty young woman. Because of this, there's hope that Kick may still like Kendall.
Mr. Vickle is the flamboyant, flower-loving goldfish aficionado in Kick's life. He never intentionally tries to get in Kick's way (due to his opinion of Kick being a nice boy) and as a result is the least affected by his stunts. Due to his opinion of Kick, he is intensely disliked by Ms. Chicarelli.
Gordie Gibble is one of the main antagonists in the show. Kick and Gordie have a strong dislike each other intently because he is another of Kick's nemeses. He hates Kick, as do lots of other people. He thinks he is superior to Kick ss seen in "Switching Gears". He is always followed by the DiPazzi Twins. They help Gordie with his cheating to beat Kick at every BMX rodeo he participates in.