In the context of China’s swift urbanization and heightened sustainability challenges, SMCEs in the construction industry play a critical role in driving both economic growth and sustainable development. This pioneering study introduces an integrative approach blending sustainability-oriented strategies (SSs) with financing guarantees, addressing key obstacles faced by these firms. Leveraging a multi-agent computational model, we dissect the dynamic interplay among construction SMCEs, governmental bodies, financial institutions, and guarantors, underscoring the transformative impact of financing guarantees on sustainable advancement. Our investigation reveals that optimally structured financing guarantees not only resolve funding challenges but also actively foster adherence to sustainability practices. This dual functionality positions such financial instruments as key enablers of SMCEs’ quest for sustainability, aligning economic objectives with ecological imperatives. Furthermore, we spotlight the transformative effect of strategic management on elevating SMCEs’ commitment to sustainable operations. Collectively, these insights offer actionable pathways for SMCEs embarking on sustainability endeavors, showcasing innovative financial solutions that do not detract from their economic prosperity.