Organizational performance increasingly depends on the ability of organizations to foster employee engagement, sustain supportive organizational cultures, and convert organizational knowledge and creativity into improved outcomes. This study examines the effects of employee engagement and sustainable organizational culture on organizational performance, with organizational innovation and knowledge-sharing practices serving as mediating mechanisms. A quantitative correlational design was employed using data collected through questionnaires from 256 employees involved in material supply activities at the Central Office of Material Supply of the Indonesian Air Force (Pusbekmatau). The data were analyzed using Structural Equation Modeling–Partial Least Squares (SEM-PLS) with SmartPLS. The findings demonstrate that employee engagement positively and significantly affects organizational innovation (β = 0.285; p < 0.001) and knowledge-sharing practices (β = 0.254; p = 0.003). Sustainable organizational culture exerts stronger positive effects on organizational innovation (β = 0.626; p < 0.001) and knowledge-sharing practices (β = 0.619; p < 0.001). Furthermore, organizational innovation (β = 0.438; p < 0.001) and knowledge-sharing practices (β = 0.498; p < 0.001) significantly enhance organizational performance. Both mediators also significantly transmit the effects of employee engagement and sustainable organizational culture on organizational performance. Notably, knowledge sharing represents the strongest indirect pathway from sustainable organizational culture to organizational performance (β = 0.308). The findings highlight that organizational performance can be strengthened by simultaneously cultivating employee engagement and a sustainable organizational culture while institutionalizing knowledge sharing and innovation as organizational mechanisms.