Objective: Integration of multi-energy complementarity is key to evolving modern power systems to achieve China's "Dual Carbon Goals". Pumped storage hydropower (PSH) plants, as a flexible and reliable regulatory energy sources, offer considerable advantages including technological maturity, economic viability, and strong compatibility with renewable generations such as wind and photovoltaic power. They also significantly contribute to grid stability, renewable energy absorption, system flexibility, and enhanced power quality. However, few studies have empirically addressed the key influencing factors and organizational mechanisms of PSH operations from a systematic multi-energy complementarity perspective, and empirical validations remain limited. To bridge this gap, this study develops and empirically validates a comprehensive management model adapted to PSH plants within multi-energy complementary systems. Methods: The study adopts a mixed-method approach, combining quantitative surveys and qualitative case analyses. Data were collected from 230 professionals engaged in various aspects of PSH project development, planning, operation, and management, ensuring wide coverage of critical operational segments. The proposed model includes six latent variables: multi-energy complementarity, overall PSH conditions, electricity pricing and market mechanisms, plant scheme selection, operational management, and project performance. The study uses structural equation modeling (SEM) with partial least squares (PLS) analysis to examine eight hypothesized pathways among these constructs. Results: Results demonstrate significant positive relationships, with all path coefficients statistically supported (p < 0.001), and key endogenous variables show high explanatory power (R² values between 0.601 and 0.826). Specifically, multi-energy complementarity and overall PSH conditions exert substantial influence on operational management and eventual project performance through mediating factors such as pricing mechanisms and scheme selection. The empirical findings highlight the importance of market-based electricity pricing and complementary energy planning in enhancing the operational efficiency and economic viability of PSH stations. Furthermore, the study introduces a validated measurement system that offers robust tools for future empirical assessments in similar contexts. Based on these insights, actionable recommendations are proposed, including the advancement of integrated multi-energy coordination mechanisms, the establishment of a multidimensional evaluation framework for PSH site and technology selection, reforms in electricity pricing and market participation models to reflect flexible regulation value, and the integration of digital-intelligent technologies for optimized operation and market responsiveness. Conclusions: This study provides both theoretical insights and practical strategies to improve the management and performance of PSH plants in multi-energy systems, thereby supporting the sustainable and high-quality development of PSH plants and contributing to national carbon neutrality objectives.