Processes of social innovation are receiving particular attention in discussions of urban development and sustainable transformation processes. In this regard, the authors consider spatial pioneers as showing particular promise. Spatial pioneers are actors who go beyond their own spatial interests and initiate and implement new solutions for local social problems. With reference to the methodology of focused ethnography, this contribution seeks to shed light on the communicative genesis and negotiation of social innovations introduced by spatial pioneers in urban neighborhoods. Using the example of a specific spatial pioneer in two very differently structured civil society groups in Berlin’s Moabit district, we illustrate that this negotiation process can be fiercely contested, met by resistance, and accompanied by conflicts that emphasize a continual struggle with innovation. Thus, specific patterns of communication, heterogeneous knowledge, mutual trust, powerful group positions, and personal innovation ambitions do not per se foster innovation, but are situationally interdependent. This suggests the need for a process-accompanying and in vivo perspective on social innovation, with a focus on the communicative genesis of these processes.