University common spaces are increasingly recognized as critical environments for social interaction and informal learning; yet empirical frameworks that integrate biophilic design, placemaking, and affective post-occupancy evaluation remain limited in educational contexts. This research adopts a post-occupancy evaluation (POE) design to assess how spatial configuration and biophilic placemaking strategies influence emotional experience, social interaction, and perceived inclusion in a redesigned university lobby serving five colleges. A structured questionnaire was administered to 212 users using the Pleasure–Arousal–Dominance (PAD) model, triangulated with systematic behavioral observations and spatial analysis. The results demonstrate that integrating biophilic elements, improving spatial organization, and introducing student-led activity areas yielded high perceived comfort (M = 3.75), balanced stimulation (M = 3.10), and a stronger sense of spatial control (M = 3.16), with significant positive correlations between biophilic integration scores and all three PAD dimensions. These findings introduce and empirically validate the concept of Socio-Biophilic Synergy and propose the Biophilic Placemaking Framework (BPF) as a unified evaluative structure, demonstrating that the intentional spatial design of the university spaces can meaningfully enhance social sustainability and emotional well-being in university environments.