The agency (micro-level) within structure (macro-level) paradigm has dominated life course research for many years as the primary conversation between life course sociology and lifespan psychology and, more recently, biology (notably, within epidemiology). However, whether the meso-level, i.e., research questions related to the question of linked lives or, as proposed here, questions of geographical and social embeddedness, appear to be of the utmost importance in life course research. In this work, I define the meso-level, relying on previous works in social psychology and geography, as the geosocial embeddedness of individual trajectories, distinguishing three perspectives: network, categorical and territorial. I also demonstrate the fruitfulness of geosocial embeddedness for illustrating via research examples of how intersecting social networks, social categories and territorial embeddedness enable the integration and organization of past research and open new research questions. This paper also argues for the integration of subjective and more objective perspectives of geosocial embeddedness. Moreover, it thereby invites life course scholars to integrate more systematic advances in social psychology and social geography or urban studies within life course theory.