As urban areas are developing and becoming increasingly important for dealing with sustainability goals and challenges, it is of the essence not to overlook the impacts created by the local, small-scale processes taking place across metropolitan regions. Based on a case study conducted in the expansive Stockholm region, this study explores the challenges associated with linking small-scale development to long-term overall strategy and development in municipal spatial planning. More specifically, it explores planning practitioners’ experiences of how local planning processes are organized to deal with established cross-cutting sustainability goals and the conditions for promoting sustainability in small-scale development projects. The results show that municipal planners face several organizational, procedural, and knowledge-related challenges that also influence the interplay between public and private actors in the process. To promote sustainable trajectories at the local level, it is necessary to devote resources and build capacity to further develop the relationship and interdependency between the processes of translation and formalization, which constitute an important link between the project-specific planning process and the overall strategy and development.