Matsukichi lives at the Maison du Wish boarding house, a residence for students preparing for university entrance exams, alongside fellow residents Yurume Aida, Sae Kawano, and Kumi Tanaka. Despite his youth, his physical appearance consistently suggests someone significantly older, creating a noticeable contrast.

He fully embraces the boarding house's relaxed and unproductive approach to studying and daily life, where residents rarely make progress toward their academic goals despite their purpose for being there. Matsukichi participates in this slow-paced, comfortable communal existence focused on everyday interactions rather than diligent exam preparation.

The arrival of Sae Kawano's younger sister introduces a potential disruption to the boarding house's established lazy routines, as she moves in to encourage her sister Sae to study seriously. Matsukichi, part of the resident group, experiences this intrusion into their habitual slothful lifestyle. The sister represents an external force that could theoretically push the group, including Matsukichi, toward change, though her effectiveness remains uncertain.

Identified as a core member of the group at Maison du Wish, his presence is noted within the dynamics of this small community of rōnin students—individuals studying outside the standard school system to retake university entrance exams. The boarding house occupies a less developed, peripheral area of Tokyo, contributing to its distinct atmosphere.