The present study investigates long-term population dynamics in Italy, 1862–2009, in light of Demographic Transitions (DTs). Under the assumption that DTs are multidimensional processes of change involving several aspects, including population structure and dynamics, an exploratory analysis was carried out in this study to verify temporal coherency of 15 indicators in Italy, identifying homogeneous time periods with distinct demographic characteristics. Indicators’ trends were identified using a multivariate statistical approach. The results of this study allow empirical testing of the assumption of temporal coherence between different aspects of a long-term DT, distinguishing distinctive population dynamics and the differential impact on population structure over two centuries. After a relatively long period of demographic stability, the time window encompassing the two World Wars—approximately between 1921 and 1951—was identified as a primary turning point of population dynamics in Italy; a second turning point was estimated at the beginning of the 1970s. These time intervals may represent conditions of dynamic equilibrium between demographic and socioeconomic contexts, highlighting latent system transitions. The study concludes by outlining the importance of a more effective integration of demographic transition theories into a broader sustainability framework, and implementing a diachronic analysis of political, economic, and social forces associated with population dynamics in both advanced economies and emerging countries.