In its 2021 strategy review, the European Central Bank's Governing Council unanimously decided to make climate change one of its priorities for the coming years. In this article, we try to understand how this change was achieved. To do so, we rely on mixed methods, studying ECB policies, speeches, exchanges with the European Parliament, and conducting semi-structured interviews. We present a detailed account of the rapid changes within the ECB regarding the climate challenge, and attempt to unpack its conditions of possibility. We show that climate integration results from the combination and hybridisation of internal dynamics and external pressures. On the one hand, the renewal of the Executive Board and modifications in organisational dynamics secured a growing coalition for a change. On the other, pressures from politicians, NGOs, academics and citizens pushed the institution to develop its expertise and provided willing insiders with further argumentative resources to push their green agenda. While these two intertwined dynamics have allowed ‘green doves’ to forge a consensus around the climate action plan, disagreements remain within the Governing Council on the scope and shape of future greening efforts.