Kōshi Sugawara, a third-year student at Karasuno High School, serves as the vice-captain and substitute setter for the boys' volleyball team. He possesses a slender build, stands 174.3 cm tall, and has light grey hair, hazel-brown eyes, and a distinctive mole under his left eye. A gentle smile is typical of his appearance, with his hair growing slightly longer after a timeskip. He attended Nagamushi Junior High, joining the volleyball club alongside Daichi and Asahi. Excited to attend Karasuno for its national volleyball reputation, they found the team in decline, lacking a proper coach and struggling to secure practice matches. Despite early tournament losses in their first year, Sugawara and his peers committed to rebuilding the team through extra practice. As vice-captain, Sugawara exhibits a soothing and supportive personality, acting as a stabilizing force. He prioritizes the team's success over individual recognition, voluntarily ceding the starting setter position to first-year prodigy Kageyama Tobio after recognizing Kageyama's superior technical skills. Though experiencing jealousy and frustration over this demotion, he suppresses these feelings to maintain team harmony, focusing instead on leadership and strategy. His dedication is evident in continuing club activities during his third year while most peers retired for academics, stating he wanted no future regrets. Sugawara's perceptiveness and tactical intelligence are key assets. He devised hand signals overnight to facilitate synchronized attacks and created verbal cues like "bring it" and "send it to me" for Kageyama and Hinata's quick strikes. During matches, he analyzes opponents from the sidelines and implements surprise tactics when substituted in, acting as a disruptive pinch server against Shiratorizawa or executing the "Calculated One-Point Two-Setter" play with Kageyama as a spiker. His unpredictability as a rarely used player gives Karasuno strategic advantages. Beneath his nurturing demeanor, Sugawara displays mischief and pride. He supported Hinata's unauthorized entry into a training camp, playfully smacked teammates during excited moments, and bragged about naming Kageyama and Hinata's "Back Minus" technique. He also showed uncharacteristic pettiness during losses, sulking after points conceded to Shiratorizawa. In the "VS Failing Grades" OVA (also referenced as "VS Akaten"), Sugawara assists Hinata and Kageyama after they fail exams and risk missing a Tokyo training camp. He coordinates study sessions with other team members and reassures them about future opportunities, though he defers to Daichi's stricter disciplinary approach. After high school, Sugawara becomes an elementary school teacher in Miyagi Prefecture as of 2018. His legacy at Karasuno endures through his emphasis on reliability, resilience, and selfless support.