Despite the increasing interest in ‘smart city’ initiatives worldwide, current literature still lacks the approaches and models that address challenges in organization and collaboration, which boost sustainability and ‘smartness’ in modern cities. This paper provides an overview of ‘smart city’ ecosystems as a mechanism to promote the expected outcomes of their sustainable development, and highlights the importance of conceptualizing cities from organizational and managerial perspectives. Representative exploratory models of ‘city organization’, which emphasize on the role of ‘governance’ and synergies, are presented to ‘decode’ complex city mechanisms and to determine key components that lead to ‘smart’ initiatives. Interesting case studies and applications are then analysed to examine the practical dimension of these approaches. As a review paper, this article lays out a general framework on the importance of ‘collaboration’, ‘governance’, ‘management’, and ‘ecosystem’. However, 'planning smartly’ and achieving ‘sustainability’ at the level of city ‘organization’ remain as challenges in this pioneering study of smart cities.