Over the past decade, widespread concern has emerged over how environmental governance can be transformed to avoid impending catastrophes such as climate change, biodiversity loss, and livelihood insecurity. A variety of approaches have emerged, focusing on either politics, technological breakthrough, social movements, or macro-economic processes as the main drivers of change. In contrast, this paper presents theoretical insights about how systemic change in environmental governance can be triggered by critical and intellectually grounded social actors in specific contexts of environment and development. Conceptualising such actors as critical action intellectuals (CAI), we analyze how CAI emerge in specific socio-environmental contexts and contribute to systemic change in governance. CAI trigger transformative change by shifting policy discourse, generating alternative evidence, and challenging dominant policy assumptions, whilst aiming to empower marginalized groups. While CAI do not work in a vacuum, nor are the sole force in transformation, we nevertheless show that the praxis of CAI within fields of environmental governance has the potential to trigger transformation. We illustrate this through three cases of natural resource governance in Nepal, Nicaragua and Guatemala, and Kenya, where the authors themselves have engaged as CAI. We contribute to theorising the ‘how’ of transformation by showing the ways CAI praxis reshape fields of governance and catalyze transformation, distinct from, and at times complementary to, other dominant drivers such as social movements, macroeconomic processes or technological breakthroughs.