To build resilient and climate-neutral cities, it is required to modify current territorial planning processes to make them more sustainable and virtuous. However, the implementation of new strategies and innovative governance models faces multiple obstacles, economic restrictions, and technical gaps. In particular, local governments often find it difficult to build structured transition processes. This article investigates how it is possible to respond effectively to the need of urban contexts to adapt to climate impacts, analyzing the case of the Climate Transition Strategy (CTS) “La Brianza Cambia Clima”, the first in Italy of this kind. Through the technical framework and the methodology described, the CTS can activate inter-municipal transformative actions through the mainstreaming of planning tools, the construction of a medium-long-term vision, and the identification of concrete and widespread actions to be implemented in the territory. This coordinated and shared strategic approach allows one to give stability, coherence, and continuity to adaptation processes involving different stakeholders and sectors of the Public Administration. Finally, it favors the implementation of multidisciplinary policies for territorial resilience on a large scale.