Kunimitsu Tezuka appears in the movie "Tennis no Oujisama: Atobe Kara no Okurimono - Kimi ni Sasageru Tennis Prince Matsuri" as part of an inter-school festival hosted by Keigo Atobe. This festival features events like a dating game and a relay race involving players from multiple schools. Atobe organizes the event to express gratitude toward a specific attendee, with contextual clues suggesting Tezuka is a primary focus due to their established rivalry and mutual respect.

Tezuka participates in the festival alongside his Seigaku teammates and players from other schools. The relay race showcases intense competition between the attending teams. The movie emphasizes lighthearted interactions and celebratory activities, highlighting camaraderie among the characters rather than tennis matches. Atobe's gesture underscores his recognition of Tezuka's significance as a rival and peer.

This portrayal aligns with Tezuka's broader character arc, where his leadership of Seigaku and unwavering dedication to tennis earn him deep respect from competitors like Atobe. The festival serves as a narrative device showcasing their relationship outside formal competitions.