["Environmental Policy and Governance, EarlyView. ", "\nABSTRACT\nExternal nongovernmental organizations (NGOs) play a pivotal role in rural environmental governance, yet little is known about how they navigate multilevel institutional barriers to enhance villages' self‐organized ecological governance. This study examines an environmental NGO in rural China to uncover the mechanisms through which exogenous actors activate endogenous governance capacity. Findings show that the NGO strengthened grassroots governance by enhancing actor interaction and performance through three interrelated mechanisms: a system‐integration mechanism leveraging multichannel embedding, an agenda‐setting mechanism combining community‐space cultivation with embedded deliberation, and a capacity‐absorption mechanism linking technical and conceptual support with trust‐building. Effective intervention also depended on professional and ethical conditions—professionalism in balancing human–nature tensions, and ethical engagement rooted in community‐based affective governance and individual self‐realization. Moreover, the NGO employed legitimacy strategies to resolve integration dilemmas, fostered villager agency through people‐centered approaches, provided alternative livelihoods to mitigate human–wildlife conflict, and promoted village organizational structures and equitable benefit‐sharing. Collectively, these mechanisms enhanced the adaptability and resilience of village self‐governance under institutional diversity and external shocks. The study offers practical insights for context‐sensitive rural development initiatives, such as China's “Ten‐Thousand Villages” program, and contributes to theoretical understanding of modernized, adaptive environmental governance in state‐centric, resource‐constrained settings.\n"]