Tooru Oikawa

Height: 184.3 cm / Weight: 72.2 kg / Highest jump reach: 335 cm / Birthday: July 20 / Favorite food: Milk bread / Recent concern: Completely ignored by the manager of Karasuno when I tried to talk to her.

A third-year student and captain of the Aoba Johsai High School volleyball team, S. His jersey number is 1. He gives nicknames to everyone indiscriminately.

An offensive setter. Known for his elegant tosses and powerful jump serves. Not only is his level of play high, but he also possesses strong communication skills, grasping the personality and habits of each teammate to enhance their game strategy. He also has a keen eye for observing opposing teams and players. During a practice match with Karasuno High School, he participated as a pinch server in the latter part due to an injury, demonstrating exceptional power and control.

He is a senior from Kageyama's middle school and has greatly influenced him in playing, as Kageyama himself said he learned blocking and serving by watching Oikawa. Recognized by Ushijima (the captain of Shiratorizawa) as a setter who can bring out 100% of the team's power, he made Kageyama think he might never be able to win against him when he scouted their practice. Known as one of the top players in the prefecture, he is aware that his results are due to the efforts of an "ordinary person." Therefore, he intensely dislikes players called "geniuses" (like Ushijima and Kageyama). He quickly noticed that Hinata and Sugawara from the Karasuno team helped Kageyama break away from being a "tyrant (lonely king)." When Kageyama came to consult about the quick attack, he gave him harsh advice. Seeing Kageyama qualify for the Spring High, he felt annoyed yet proud of Kageyama's play.

Despite his somewhat frivolous nature in everyday life, he has a charismatic presence in games that can instantly change the team's atmosphere. With his handsome features, he is very popular among girls, often charming them, which earns the ire of Iwaizumi. Kageyama, known as "the king," fears him, leading Hinata to call him "the Great King." His motto is "If you're going to hit it, break it." He won the Best Setter award at the prefectural middle school general sports festival. After losing in the semifinals of the Spring High preliminaries, he chose not to go to Shiratorizawa Academy for reasons Ushijima pointed out as "You've lost your way... for a worthless pride..." to which he retorted, "Remember this worthless pride of mine."

After graduating from high school, he moved to Argentina to play in the local professional league at CA San Juan, following a player he admires, José Blanco. During the team's trip to Brazil, he unexpectedly reunited with Hinata and they caught up on each other's recent activities and played beach volleyball. When parting, he started calling Hinata "Shouyou." In the final episode, it was revealed that he had naturalized in Argentina and became a representative for Argentina in the 2021 Olympics, happily reuniting with Hinata.

In the anime, he was seen humming the theme song of Yagiyama Benyland and the cheer song of the Tohoku Rakuten Golden Eagles.