This study examines the emergence of care as a commoning practice within grassroots movements by focusing on Sōgidan, an activist group supporting rough sleepers in San’ya, Tokyo. San’ya is yoseba (day labor auction market), a historical urban margin turning into a service hub. Produced as cheap, disposable labor in the process of Japanese modernization, Japan’s day laborers were enclaved in yoseba and left without social protection after the economic bubble burst. However, they were not merely victims; they embodied a rebellious subjectivity, actively breaking away from the oppressive society. Despite welfare provisions after the 2000s, many day laborers refused aid and continued to sleep on the streets. Through extensive archival research, ethnographic observation, and in-depth interviews, this paper illuminates how Sōgidan has developed strategies of care to relate to the underclass, the historical others who refuse aid. Sōgidan embodies and carries forward the underclass movement, which uniquely echoed feminist ethics of care. It also initiates the creation of the radical commons, reconfiguring the distance between individuals and collectives, and sharing precariousness differently from capitalist norms. By linking Sōgidan’s practices to feminist ethics of care, this research contributes to opening up new perspectives of care and in(ter)dependence toward the commons.