Gaogao-San operates as a recurring mentor in the Challenge Island narrative, consistently appearing throughout Shimajirō and his friends' theatrical adventures. He functions as a knowledgeable guide during crises, aiding protagonists when realms like Heroland face hostile threats. His interactions focus on directing Shimajirō, Mimirin, Nyakkii, and Torippii, often summoning them during pivotal moments. In live-action segments, performers embody him through distinctive mascot costumes.

Utilizing specialized vehicles such as the "Dokodemo Sidecar," he facilitates interdimensional travel, enabling access to fantastical worlds like Heroland or picture-book realms. His role includes organizing and overseeing group activities, reinforcing his narrative authority. During the Heroland incident, he directly collaborates with Shimajirō and allies like Ratman to confront antagonists endangering the realm, demonstrating active conflict resolution. Across documented appearances, his presence remains confined to supportive capacities.