The emergence of organic planning practices in the Netherlands introduces new, non-conventional, local actors initiating bottom-up urban developments. Dissatisfied with conventional practices and using opportunities during the 2008 financial crisis, these actors aim to create social value, thus challenging prevailing institutions. Intrigued by such actors becoming more present and influential in urban planning and development processes, we aim to identify who they are. We use social entrepreneurship and niche formation theories to analyse and identify three types of social entrepreneurs. The first are early pioneers, adopting roles of a developer and end-user, but lacking position and power to realize goals. Secondly, by acting as boundary spanners and niche entrepreneurs, they evolve towards consolidated third sector organizations in the position to realize developments. A third type are intermediate agents facilitating developments as boundary spanners and policy entrepreneurs, without pursuing urban development themselves but aiming at realizing broader policy goals. Our general typology provides a rich picture of actors involved in bottom-up urban developments by applying theories from domains of innovation management and business transition management to urban planning and development studies. It shows that the social entrepreneurs in bottom-up urban development can be considered the result of social innovation, but this social innovation is set within a neoliberal context, and in many cases passively or actively conditioned by states and markets.