Sustainable infrastructure development is a cornerstone of national economic resilience, environmental stewardship, and social equity. As nations confront the dual pressures of rapid urbanization and climate change, the strategic oversight of construction contracts in nationally significant sectors—such as transportation, energy, water, and housing—has become essential for ensuring long-term value creation. Yet, these megaprojects are frequently undermined by fragmented governance, inadequate risk allocation, cost escalations, and non-compliance with environmental and labor standards. This paper presents a strategic framework for contract oversight that aligns infrastructure delivery with sustainability objectives while maintaining fiscal discipline and legal integrity. The analysis begins with a macro-level overview of the governance challenges plaguing large-scale construction across key sectors. It identifies gaps in traditional contract administration approaches that fail to anticipate complexity, adapt to changing circumstances, or enforce accountability. By synthesizing lessons from global infrastructure case studies, the paper highlights the need for integrated oversight mechanisms that combine performance-based contracting, stakeholder transparency, and adaptive project controls. Special attention is given to institutional tools such as independent contract audit units, public-private partnership (PPP) governance boards, and digital platforms for tracking milestones and budget performance. The role of sustainability clauses—covering carbon reduction, resource efficiency, and social inclusion—is explored within contract structuring. The proposed oversight model supports early risk detection, enhances inter-agency coordination, and ensures that strategic infrastructure investments align with national development priorities and international commitments. Ultimately, this paper provides a roadmap for policymakers, engineers, and infrastructure financiers to reform contract governance and embed sustainability across the full project lifecycle in nationally significant construction sectors.