Kyōtani is an easily identifiable character, particularly due to his short-cropped blond hair with two black stripes running across the sides of his head, just above the ears. He is one of the shortest members of the team though this usually gets overlooked because of the rest of his appearance. His honey brown eyes are sharp and appear fierce and hostile (he almost appears to be wearing eye-liner, or has dark bags beneath his eyes), and he has small eyebrows. He lives up to his nickname of "kyōken" or "Mad Dog", given from the the start of his given and surname (though this nickname was not necessarily made up by Oikawa to exemplify his fierce and brash personality, and different kanji are used).
He's said to have the best ability among the second years at Aobajohsai High, but his brash attitude is cause for poor relationships with other members of the volleyball team. He is seen to be hot-tempered and always has a frown on his face. He doesn't seem to show any respect for the third years (besides Iwaizumi), irritating them and shocking the first years upon Kentaro's return to the team. He is extremely strong, and he can only hit the ball with his full strength or he "doesn't feel satisfied." He is also shown to display some violence (intentional or not is unknown), as he shoves multiple characters throughout the show knocking them to the floor on some occasions. It seems Yahaba is one of the only people, besides Iwaizumi, that is able to effectively calm him down and get him to focus when he loses control of himself.
Before high school, Kyōtani played volleyball at Minamisan Junior High (#4). It is revealed that he has not played with the Aobajohsai team outside of a few practice matches due to his uncooperative attitude.
According to the coach, Kyōtani is a slow-starter who requires a lot of support to get going. He seems to do recklessly dangerous plays with no regard for game situation, such as knocking teammates over to spike the ball out of bounds with Karasuno at set point even though it wasn't tossed to him just to vent his frustration of not starting. By doing an approach run that's close to the net, he can do an insane inner spike that can cut across the blockers from a spot right beside them. He can also do a sideways jump from behind the setter to spike and surprise the opponent. He dislikes doing feints because he prefers to spike at full power. According to Coach Ukai, Kyōtani's plays are risky, so he's most likely a double-edged sword. His plays generally surprise his own teammates as well, and they are often enough to shake the unified dynamic of the team (this likely created some openings during Karasuno's second official game with Seijou while he was on the court), but he can also make a very valuable decoy, even without him recognizing that talent. As a server, he often overpowers his jump serves as he considers himself a power player, but has dialled it back after Yahaba's lecture.
According to Oikawa, Kyōtani has real jumping power, and his back & abdominal muscles are exceptional. He amasses power with the full bend of his body and then snaps forward, using his whole body in the way he plays. His cut shot involves him running parallel to the net and spike cross court to bypass direct blockers. Coach Ukai also noted his great body control that allowed him to spike with his left hand when necessary.
Jumping Reach: 327 cm
While Oikawa calls him "Mad Dog-chan," Kyōtani was instinctively wary of him, jumping back when Oikawa got close. Oikawa seems to appreciate Kyōtani's skill, and wants to make him a better player, saying to himself that he wishes to "sharpen [his] fangs." Despite this, Kyōtani does not listen or respond the same way to Oikawa that he does to Iwaizumi, much to the former's irritation and seems to be either highly irritated or highly nervous around him.
He's known to only listen to Iwaizumi's words and respond to his upperclassman, as he had challenged Iwaizumi to multiple athletic competitions and lost to him every time. When Kyōtani makes a dangerous move and Oikawa doesn't know what to do about it, Iwaizumi is the one who scolds him and actually hits him. Kunimi refers to this relationship as Kyōtani seeing Iwaizumi as the 'alpha-dog'.
Although they're in the same grade, Yahaba is extremely hostile and critical towards Kyōtani, more so than the rest of the players. At Kyōtani's return, the first thing Yahaba does is scold him. Even though he recognizes his talent, Yahaba doesn't seem to be intimidated by Kyōtani. This can be seen when Yahaba slams him against a wall and lectures him about respecting their senpai and asks Kyōtani to lend them his strength . His words seem to affect Kyōtani, who after that seems to cool down a little and get his head in the game as an actual part of the team.
- Favorite food: Hamima Chicken
- Current concern: Lawson's new "Kara Age Kun" is hard to throw away.
- The Kara Age Kun is a unique dish of fried chicken bits served by the Lawson franchise. To attract more clients, they use cute packages with mascots for carrying the food.
- The reason for his nickname given by Oikawa is because "kyōken" means mad dog, taken from Kyōtani Kentaro. However, the kanji is entirely different.
- His star sign is Sagittarius.
- According to the anime, he picked no.4 in middle school because he admired a player in the National team who played with the same number and was also known as a powerful wing spiker. He dyed his hair blonde, also because of him.
- It has been shown twice that he seems to have a dog of some kind with it first appearing as a puppy then shown later as an adult.
- He has a habit of licking his lips before hitting a volleyball.
- Whenever it shows him as a child sitting in the stands watching a volleyball game beside him is a male that looks like him, with short black hair and the same marks around his eyes that he possesses. This implies Kyōtani was there with his father, or possibly an older brother.
- Kentarō (賢太郎) - Capable Excessive Son
- Kyōtani (京谷) - Capital City Valley