In this paper we trace the institutional history and rationale of the Earth System Science Partnership by studying the practical and epistemic contributions of the International Geosphere-Biosphere Programme and the International Human Dimensions Programme respectively. While the main aim of our study is to offer an empirical understanding of how this new partnership for the integrated study of the Earth System has come about, the paper also conceptualises the scientific practices and modes of thought represented by the ESSP as a central form of agency in Earth System governance. In order to understand the formation of governance practices in the Earth System, we argue that it is necessary to critically scrutinise the diverse set of knowledges and practices that have constituted the Earth System as a thinkable and governable domain.Earth System Governmentalit