For the last decade, urban actors around the globe have been struggling to adapt to a post-crisis and austerity context through increasing social mobilization and experimentation, calling for an urban democracy renewal and challenging established neoliberal urban regimes and governance systems. This has triggered social innovations, in which novel collaborative formulas have been envisioned and implemented. In particular, civil-public collaborations (CPCs) have come to the fore as an empowering alternative to the well-established private–public partnerships (PPP). This article examines the conditions of possibility, enabling mechanisms and constraints for the emergence of innovative multi-actor collaborations (IMACs). For this aim, we developed a three-fold analytical framework combining social innovation, public governance, and urban regime theory. We applied this framework to the case of the so-called “government of change” in Madrid between 2015 and 2019. After exploring the pre-2015 context, the institutional innovations implemented once Ahora Madrid accessed the local government, and the post-2019 context, it points to the preconditions that allowed experimentation with IMAC, identifies the institutional mechanisms and governance innovations that support their emergence, and assesses to what extent and how power to act was created and used to accomplish urban regime change.