Since the adoption of the Paris Agreement, the focus of the United Nations climate regime has shifted from forging consensus among national governments toward animating implementation activity across multiple levels. Based on a case study of the Global Climate Action Portal—an online database designed to document nonstate actor climate commitments and implementation efforts—we trace, conceptualize, and assess how the roles of data, data infrastructures, and actor constellations have changed as a result of this shift. We argue that in the pre-COP21 negotiation phase, the United Nations Climate Secretariat strategically used the database to orchestrate and leverage nonstate actor commitments to exert pressure on intergovernmental negotiations. By contrast, in the post-COP21 implementation phase, the Secretariat, in collaboration with climate data specialists, is seeking to develop the portal to track and animate implementation activity. Given these developments, we discuss the potential and limitations of data-driven climate governance and set out avenues for future research.