Ed Zigler was a champion for underprivileged youth, one who worked alongside communities to fight for long-lasting systemic changes that were informed by his lifespan and ecological perspective on the development of the whole child. This paper reports on the development, implementation, and preliminary outcomes of an intervention that embodied the Zigler approach by adopting a community participatory research lens to integrate complementary insights across community-based providers (promotoras), Latinx immigrant families, and developmental psychologists in the service of promoting parent–child relationship quality and preventing youth aggression and violence. Analyses from the first 112 Latinx mother–youth dyad participants (46% female children, ages 8–17) in the resultant, Confía en mí, Confío en ti, eight-week intervention revealed significant pre–post increases in purported mechanisms of change (i.e., attachment security, reflective functioning) and early intervention outcomes (i.e., depressive, anxiety, and externalizing problems). Treatment responses varied by youth age. A case analysis illustrated the lived experiences of the women and children served by this intervention. We discuss future directions for the program, as well as challenges to its sustainability. Finally, we consider Ed's legacy as we discuss the contributions of this work to developmental science and our understanding of attachment relationships among low-income immigrant Latinx families.