Jirō Jō, known as Joji, forms one half of the nearly identical Jō twins. Initially seeking romantic admiration through athletics, Joji and his brother Jota joined Kansei University’s track team at Haiji Kiyose’s persuasion. Their motivations evolved from vanity to sincere dedication, with Joji cultivating a profound connection to running that prompts Jota to recognize his younger brother’s potential to outpace him.

Joji’s journey emphasizes incremental growth in collaboration and race strategy. He and Jota seamlessly alternate leadership during training and competitions, leveraging their synergy to enhance pacing and bolster teammates. This dynamic proves pivotal in key events such as the Hakone Ekiden relay, where their coordination elevates the team’s standing. Beyond the main narrative, Joji remains active with Kansei’s expanding track team, reflecting his enduring dedication. While adaptations depict minor visual contrasts—shorter blonde hair in anime versus spiky red in manga—these variations remain cosmetic, leaving their narrative roles unchanged.