The transition to a zero-emissions world entails vast political economic restructuring. How resources are mobilized, what sorts of technological infrastructures are constructed, who funds, controls and has claim to profits from investments contributing to the green transition will shape political economies for generations to come. This article suggests that early 20th-century American institutionalism and subsequent legal institutionalist literatures provide a valuable resource for energy transitions scholars and other social scientists, activists, and policy-makers of the energy transition. The article summarizes some of the major lines of thought in classical and legal institutionalism and briefly outlines three areas in which they can inform thinking about political economies of the Anthropocene. First, these literatures are generative of creative thinking on how business activity is organized and help overcome reductionist public-private dichotomies. Second, the history of institutionalist and progressive thought in the New Deal-era runs parallel, in revealing ways, to thinking based on environmental, social and governmental (ESG) principles in the present. Lastly, the article discusses radical proposals for transformation of private property and investment in the thought of institutionalist Adolf Berle relevant to simultaneously addressing both climate and inequality crises.