In the field of global environmental governance South Korea stands out. Since 2005 it has been the initiator and central node in a majority of international networks and organizations promoting green growth. Based on new theoretical approaches and empirical analysis, this article highlights the significance of Korea’s middle power diplomacy in relation to green growth governance, establishing it as a ‘Green Middle Power.’ Middle power analyses of Korea usually portray it as a regionally constrained and secondary actor in global governance. This article supplements middle power theory’s behavioral approach with a strategic action approach inspired by Bourdieu’s practice theory, which it applies to an original database of >1,000 sources, 18 interviews, and 10 participatory observations. The article argues that Korea has become a primary actor in global environmental governance by demonstrating how Korea has established a sub-field of green growth governance through a wide range of strategic moves.