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.

Task interdependence is essential in sustainable cooperation, conflict prevention, and performance improvement of public–private partnership (PPP) project teams and promotes the sustainable development of PPP projects. Based on the theoretical logic of Input–Process–Output (IPO), integrating Team Process Theory and Leader–Member Exchange (LMX) Theory, we constructed a mediated model of task interdependence, team reflection, team performance, and leader–member exchange differentiation in PPP projects. Based on this, we conducted questionnaire research and research analysis on 168 PPP project teams. The results of the study indicate that task interdependence in PPP projects has a significant positive effect on team performance, and there is a significant mediating role of team reflection in the relationship between task interdependence and team performance. The leader–member exchange differentiation in teams not only moderates the relationship between task interdependence and team reflection and team reflection and team performance but also further moderates the indirect effect of task interdependence in PPP projects on team performance through team reflection. The findings extend the impact effects of task interdependence in engineering projects, as well as the moderating mechanisms of leader–member exchange differentiation in Chinese organizational scenarios, providing lessons for PPP project team performance management and sustainable development of PPP projects.