Koichiro Iketani leads the Akina SpeedStars street racing team. He pumps gas at an Esso station in Shibukawa alongside Takumi Fujiwara and Itsuki Takeuchi, introducing them to Gunma's racing scene by bringing them to his team on Mount Akina. His childhood involved fishing at Lake Akina with his companion Kenji, and he earned his driver's license at 18 through driving school. He pilots a Nissan Silvia K's (S13), possessing moderate driving skills that make him the SpeedStars' most capable member, though not an elite racer.

Seeing the Akagi RedSuns outpace his team during practice, Iketani urgently hunts for Akina's rumored fastest driver, the "Eight-Six." His search leads to Bunta Fujiwara's tofu shop, where he requests Bunta race for them. Bunta refuses, stating skill requires persistent practice and road experience. Later, practicing alone on Akina, Iketani swerves to avoid an oncoming car, crashes into a guardrail, suffers minor injuries, and damages his Silvia. This crash deepens his desperation to recruit Bunta against the RedSuns.

Iketani reacts with disbelief when Takumi arrives for the race in the Eight-Six instead of Bunta. After questioning Takumi about his tofu deliveries, he realizes Takumi is the driver who previously beat Keisuke Takahashi. Despite SpeedStars protests, Iketani insists Takumi races, recognizing his raw talent.

Years later, Iketani manages an ENEOS petrol station in Shibukawa. He remains unmarried, holding unresolved feelings from a past romance with Mako Sato. His receding hairline irritates him when mentioned. He follows the MFG racing series with Itsuki and Kenji, maintaining his automotive connection despite retiring from competition.