Abstract. Service systems’ capabilities to generate (positive or negative) externalities and their impact at the societal level has remained under- investigated so far. This study addresses this gap and explores how an innovative organizational architecture based on (i) a network of competent actors, (ii) an (ICT-enabled) platform serving as a network commons and (iii) a shared institutional logic and worldview enables the emergence and evolution of a service ecosystem with strong positive externalities. It was conducted an in-depth longitudinal study (2013-2016) on an ICT-enabled community of IT professionals, aimed to provide unemployed professionals with employment opportunities while also providing small and micro enterprises and non-profit organizations with affordable, high-level IT services. The case-study shows that the presence of non-profit organizations in the service ecosystem strongly influences the service ecosystem’s institutional logic and worldview and facilitates sustainability-oriented self-organizing throughout the ecosystem.