The urgent need to balance affordability, sustainability, and well-being amidst constrained budgets has catalyzed an exploration into innovative technologies and sustainable practices as potential solutions to this complex challenge. This study aims to bridge the knowledge gap by developing a comprehensive framework that outlines the Critical Success Factors (CSFs) essential for the implementation of Innovative, Sustainable, and Affordable Rental Housing (ISARH) projects. The study employs a detailed methodology, which begins with a Systematic Literature Review (SLR) to establish a foundational understanding of existing CSFs. This is complemented by an expert opinion survey, utilizing a five-point Likert scale to capture diverse perspectives, which is refined through the Fuzzy Delphi Method (FDM)—an analytical tool suited for complex decision-making scenarios. The framework’s validation includes rigorous analysis with the Wilcoxon matched-pairs signed-ranks test, ensuring the reliability of the results. Within this framework, 32 critical CSFs were identified and categorized under four key sustainability domains—social, economic, environmental, and institutional—deemed crucial for achieving comprehensive ISARH. The top-ranking CSFs included ‘affordability based on income’, ‘design flexibility’, ‘use of sustainable building materials for construction’, ‘low presence of environmental problems in the surrounding’, and ‘tenure security’. This paper significantly contributes to the discourse on urban planning and housing policy by providing a methodological blueprint for assessing the viability and implementation strategies of ISARH projects. It advocates for targeted policy interventions and innovative practices to address the pressing needs of low-income populations, thereby contributing to sustainable development and equitable growth in urban areas.