Jun is a relatively tall individual standing about 204 cm. Hence, this makes him the most elevated character in the series. He has black buzz-cut hair with eyes of the same corresponding color. His jersey number is 18.
Jun is a candid individual and is a man of few words. In fact, he is the complete opposite of his brother. He is not very outgoing or social. Due to his aggressive and introverted personality, he was at odds with his teammates at Shinmaruko High during the Inter-High district qualifiers match against Kuzuryū High.
Jun started playing basketball under the influence of his older brother. He attended Yagiri Junior High. Due to his immense strength, Jun dominated his middle school years by brutally crushing his adversaries. He averaged about 36 points per game and had blocks and rebounds in double figures. Kota Igarashi's former teammate at Shinjo Towa Academy played against him and broke his collarbone. Although Jun surpasses his brother, Shinichi, in every aspect of physical ability, he is mentally inexperienced and has an aggressive personality, so he had few friends until middle school. Jun is also a very prideful individual. Since being the younger sibling of Shinichi, who is considered one of the top 5 players in the Kanagawa region, Jun turned down recommendations to enter Shinmaruko High. In fact, to surpass his brother, he enrolled in Shinmaruko High on his own talent and merit.
Jun is one of the best centers in the series. Similar to his brother, Shinichi, his domain is the entire paint area. His immense size and strength make him a formidable rebounder and an excellent shot blocker. Jun's tall and muscular physic enables him to overpower his opponents. He can effectively make dunks, layups, and free throws.
- The name Jun means "pure, honest and genuine."
- Jun's surname Chiba (千葉) means "thousand leaves."