In recent years, the concept of smart sustainable cities has come to the fore. And it is rapidly gaining momentum and worldwide attention as a promising response to the challenge of urban sustainability. This pertains particularly to ecologically and technologically advanced nations. This paper provides a comprehensive overview of the field of smart (and) sustainable cities in terms of its underlying foundations and assumptions, state–of–the art research and development, research opportunities and horizons, emerging scientific and technological trends, and future planning practices. As to the design strategy, the paper reviews existing sustainable city models and smart city approaches. Their strengths and weaknesses are discussed with particular emphasis being placed on the extent to which the former contributes to the goals of sustainable development and whether the latter incorporates these goals. To identify the related challenges, those models and approaches are evaluated and compared against each other in line with the notion of sustainability. The gaps in the research within the field of smart sustainable cities are identified in accordance with and beyond the research being proposed. As a result, an integrated approach is proposed based on an applied theoretical perspective to align the existing problems and solutions identification for future practices in the area of smart sustainable urban planning and development. As to the findings, the paper shows that critical issues remain unsettled, less explored, largely ignored, and theoretically underdeveloped for applied purposes concerning existing models of sustainable urban form as to their contribution to sustainability, among other things. It also reveals that numerous research opportunities are available and can be realized in the realm of smart sustainable cities. Our perspective on the topic in this regard is to develop a theoretically and practically convincing model of smart sustainable city or a framework for strategic smart sustainable urban development. This model or framework aims to address the key limitations, uncertainties, paradoxes, and fallacies pertaining to existing models of sustainable urban form—with support of ICT of the new wave of computing and the underlying big data and context–aware computing technologies and their advanced applications. We conclude that the applied theoretical inquiry into smart sustainable cities of the future is deemed of high pertinence and importance—given that the research in the field is still in its early stages, and that the subject matter draws upon contemporary and influential theories with practical applications. The comprehensive overview of and critique on existing work on smart (and) sustainable cities provide a valuable and seminal reference for researchers and practitioners in related research communities and the necessary material to inform these communities of the latest developments in the area of smart sustainable urban planning and development. In addition, the proposed integrated approach is believed to be the first of its kind and has not been, to the best of one’s knowledge, produced elsewhere.