This study examines how collaborative public relations management shapes community-based branding at a pesantren-based secondary school in Indonesia, where market-oriented branding frameworks may be insufficient. Using an intrinsic case-study design within a constructivist paradigm, the study draws on semi-structured interviews with 16 informants across six stakeholder categories, participant observation, and document analysis at SMA Unggulan Haf-Sa BPPT Genggong, East Java. Data were analyzed through reflexive thematic analysis . Three themes were constructed: (1) parents and alumni act as co-producers of institutional identity through practical support, informal promotion, and financial contribution; (2) community leaders provide social legitimacy that extends the school's reputation through pengajian and village forums; and (3) digital media function as infrastructure for participatory branding, with community networks amplifying institutionally coordinated content. Divergent accounts qualify this picture: collaboration is effortful, concentrated in an active minority, and accompanied by reduced message control. The study specifies relational trust as the mechanism linking community engagement to branding, and proposes a testable coordination–amplification model in which the public relations unit facilitates rather than controls collective identity. The findings ground collaborative and co-creational public relations arguments empirically in a faith-based K–12 setting. In similar settings, public relations units may benefit from prioritizing relationship maintenance over message production, though the trade-off with message control warrants deliberate management