The quest for sustainable urban development requires innovative planning approaches more apt to cater for transformative action. Based on a case study approach, this study aims to explore the potential for local planning to develop practical approaches able to accelerate the transition towards sustainable urban development. To guide spatial development towards sustainability, the analysis of the results shows that local planners need to envision a process design as to advance the understanding of how a site or area can be developed. The act of process design involves pending between processes of contextualization (i.e. exploring five distinguishable domains of planning inquiry) and concretization (i.e. deciding upon a course of action by executing activities that form a process trajectory). Regarding the potential of local planning to develop transformative approaches, it is concluded that: (i) local planners possess capabilities that allow them to probe the future of places and produce insights about prospective change, (ii) the transformative capacity of local planning practices is bound to the development of the identified domains of planning inquiry and (iii) forthcoming evaluations organized around the act of process design can reveal insights regarding the possibilities to put the notion of sustainability into practice at the local level.