The aim of this paper is to make sense of the complexity of modern project management by proposing four hierarchical levels to categorize ‘projects’. It argues for emphasising interdisciplinary levels in order to address ‘higher level’ interdisciplinary issues such as social innovation, including sustainability and legacy. Besides the technical/operational and strategic (firm) levels, it calls for two interdisciplinary levels: one for the national government institutional level and another for inter-government level to address grand challenges such as climate change and energy transition to sustainability. At these interdisciplinary levels, broader issues related to social innovation, sustainability and legacy come to the fore. Also the paper proposes the terms project policy and project impact in order to broaden the scope of project management usually too much focused on project implementation. Project policy encompasses the whole lifecycle of the project, including the period before its implementation and after its termination. Also the paper calls for specific policies to address project impact (especially for the period after project termination) as this represents a major challenge for major projects at the higher levels to deliver sustainable outcomes.