Located within Australia's largest city, the iconic Sydney Harbour sustains a highly diverse marine environment, where local managers operate within a layered and complex governance structure that is yet to adopt a holistic integrated approach to resource management. Planning a sustainable future for our sea-bounded society requires enhanced understanding of the responses of natural and socio-economic systems to human actions, and improved management of the multiple human uses of our marine ecosystems. Recent criticism to marine resource management systems in the Sydney Harbour catchment area include lack of integration of interactions between ecological and social systems; poor definition of management targets and outcome-oriented management plans; and insufficient integration between catchment and coastal planning. Integrated resource planning and management can address identified weaknesses, and Ecosystem-Based Marine Spatial Planning (EBA-MSP) offers a strategic framework that can facilitate a more structured approach to resource planning, recognizing the full array of interactions within ecosystems, including human uses. This research proposed the adoption of the EBA-MSP framework to improve the methodological approach to resource planning and enhance the integration of the social dimension into management plans, using Manly Local Government Area as a representative catchment area of the harbour. The research aimed to enhance local government capacity to develop integrated coastal management plans consistent with EBA-MSP principles, accounting for key social, economic and environmental factors relevant to a sustainable management of the harbour. In fulfilling this aim, the research established specific objectives of appraising EBA-MSP case studies, assessing coastal planning and resource management plans at local scale, identifying and characterising socio-economic and biological targets, and designing and developing a prototype Decision Support Tool (DST) based on a Bayesian Belief Network (BBN) to support planning processes. This research provides initial theoretical and practical foundations for local government to adopt EBA-MSP as an overarching planning framework that can deliver healthy resilient marine ecosystems sustaining human uses. The BBN-based DST developed here can play an important role in continuing to increase government capacity to develop integrated resource management plans under an EBA-MSP approach.