Agroecological transitions in the Global South often unfold within complex ecologies of intermediation, shaped by atomised project logics, donor dependence and transnational interventions. In such contexts, the coexistence of multiple intermediaries - NGOs, research bodies, farmer organisations, etc. - can hinder rather than foster niche development. This article analyses how orchestration can emerge as a governance mechanism that provides cooperation and symbiosis within such fragmented ecologies of intermediation. Drawing on a longitudinal study of the Senegalese agroecological niche (1980–2025), we trace how a locally rooted NGO mobilised and steered an advocacy coalition - DyTAES (French acronym for ‘Dynamique pour une transition agroécologique au Sénégal’) - to connect grassroot initiatives with territorial coalitions, national policy arenas and transnational agendas. We therefore conceptualise niche orchestration as a specific governance mechanism whereby a central and resourceful actor coordinates an ecologies of intermediation to generate momentum for the niche. Orchestration is not a single act of management, but an iterative, multi-scalar process that unfolds over time through the strategic integration of multiple systemic intermediation functions. Such centralization and functional bundling are uncommon, as intermediation efforts in broader ecologies are usually spread across multiple actors. The Senegalese experience demonstrates both the potential and the risks of niche orchestration, highlighting how it can accelerate transitions while raising concerns of dependency and co-optation. Future research may test and refine this perspective using other study cases, including in Global North contexts and non-agricultural context.