This study investigates the impact of sustainable project management practices on project success and the moderating role of corporate policies and practices. Using a quantitative approach, data were collected from 398 manufacturing firms in Kumasi, Ashanti region, through structured questionnaires and analysed using SmartPLS 4. The results reveal a significant positive effect of SPMP on PS, affirming that sustainable practices enhance operational and strategic outcomes. CPP also demonstrated a direct positive effect on PS, suggesting that supportive governance frameworks reinforce successful project delivery. The interaction between SPMP and CPP yielded a negative moderating effect, indicating that under certain conditions, rigid corporate policies may dampen the benefits of sustainability-focused project management. These results highlight the importance of adaptable, synergistic corporate frameworks to optimise sustainability initiatives. This study contributes by contextualising sustainable project management practices within a broader organisational framework and offers actionable insights for policymakers and project managers pursuing sustainable development.