<p>This investigation focuses on applying an innovative strategic planning model for place marketing to implement a sustainable development process for touristic territories. The purpose of this study is to propose a strategic place marketing approach for the sustainable development of four Local Territorial Systems (LTSs) located in the Province of Lecce, Southern Italy, by examining their main determinants. Two intermediate objectives are established: 1) to evaluate the determinants of sustainable development of LTSs—specifically, the attractiveness of the competitive environment and the competitive capacity of the various LTSs—by analyzing the competitive positioning of each LTS; and 2) to define the prospective positioning by forecasting future dimensions of sustainable development, attractiveness, and competitive capacity. The outcomes of a prospective analysis are valuable to inform and develop distinctive place marketing investment strategies—Penetration investments, Rebuilding investments, Selection investments, and Reduction investments. This approach provides a groundbreaking tool to guide the choices of policymakers and institutions, and to inform their strategies. The specificity of LTSs can be leveraged to prepare suitable territorial offers and achieve sustainable development by shifting the focus of state government planning decisions from individual cities to cohesive territorial systems.</p>