Over the last decade, social entrepreneurs have become central figures in the innovation literature. However the literature on social entrepreneurship is mainly focused on the issue of formulating and protecting a social purpose, but does not address the question of the emergence of radical innovations to achieve the desired social change. The booming literature on social innovation does not describe this emergence either: few studies have addressed how social entrepreneurs can actually develop social innovation or what their skills should be to develop social innovation. This paper aims to contribute to deepen our understanding of the relationships between social entrepreneurs and social innovation by exploring specifically the role of the common purpose as a key factor for social entrepreneurs to design radical social innovation(s). First, we review the literature on social entrepreneurship and social innovation, and we highlight its inherent “innovation paradox”: because innovation is thought to be intrinsic to social entrepreneurship, social innovation has virtually never been theorized per se. We underline that the social purpose is key in social entrepreneurship and hypothesize that it can play a crucial role to sustain radical innovation processes. Then, we present a longitudinal case study of a French SME, Nutriset, to investigate the link between social entrepreneurship, social innovation and the common purpose. Based on 52 individual semi-structured interviews conducted between March 2011 and January 2013, our findings suggest that Nutriset reconfigured the field of treatment of severe malnutrition for young children, renewing the common purpose on this issue and impacting the capabilities of other actors in the ecosystem. Our analysis shows that Nutriset was able to renew several times its purpose in a way that stimulated collaborative innovation: on the one hand, it allowed the firm to redefine (and generally extend) its activities in order to develop innovation, and on the other hand it led to involve new partners in the process. Our proposal is that social entrepreneurs need to create social missions that are both “generative”, which means likely to generate conceptual cognitive breakthrough instead of focusing on the already known aspects of the social issue to be solved, and “common”, that is, designed to gather around critical partners in an ever-growing relevant ecosystem. In doing so, it helps to build a bridge between the two elements of social entrepreneurship – mission and innovation. This research opens up perspectives for future research on the articulation of innovation processes and social entrepreneurship, regarding for instance the study of key factors for the development of social innovation, an opening of the black box of the design of social innovation, or the analysis of the adhesion and cohesion mechanisms during innovation process within established companies that carry out a social prospect.
