This paper is studying sustainability from below by focusing empirical data about the role of local public officials and their capacity and propensity to consider aspects of sustainability in two Swedish case studies; (1) one is about a radical change of land use in Örebro, a relatively big Swedish city (125 000 inhabitants), which resulted in a project of environmental restoration and development instead of a traffic-roate project which was terminated, (2) the other case is about a radical renewal of residential areas in Hällefors, a small, declining industrial city. In both cases the role of public officials was decisive for the direction thatthe two projects took. Even though the meaning of sustainability concept is debatable, it is obvious that important aspects of it are considered in the two cases. The two officials which were project leaders can be described as inside activistswith fieryspirits. They were inside in the sense that they were employed by the local authorities. However, they did not accomplish those changes by themselves, with municipal resources. They were really good at networking to mobilise different types of resources, both in vertical and horisontal dimensions. The paper starts theorizing on the character of those networks and the role of inside activists.