Sustainable collaboration among teams drives sustainable public–private partnership (PPP) projects, and the interactions, perceptions, and behaviors of project teams with ad hoc decision-making power critically impact collaborative performance in PPP contexts. While the role relationships between subjective interdependence, collective behaviors, team processes, and performance in PPP project teams are yet to be clarified, further validation is needed to embed this logic in project management. This study aims to clarify the role relationships among the four variables of team interdependence, team interaction, team performance, and government participation. Through an empirical investigation of the data of 367 samples of PPP project teams and data analysis by SPSS 26.0 and Amos 23.0, it is found that team interdependence (task interdependence, result interdependence) has a significant positive effect on cooperative performance, and team interaction plays a mediating role in this process. Compared with enterprises with low government share, team interdependence with high government share has a significant positive effect on the team cooperation performance of PPP projects and has a positive moderating effect on the influence mechanism of team cooperation performance. Based on this, this paper proposes strategies for PPP project team management and sustainable development. It suggests corresponding suggestions for improving PPP project team performance and sustainable development.