Public–Private Partnership (PPP) projects have become one of the most widely adopted procurement approaches for delivering large-scale infrastructure worldwide. These arrangements are defined as long-term, performance-based contracts between public and private entities for the creation, renovation, or management of public assets, where the private party assumes significant financial and management risks in exchange for potential rewards. By leveraging private sector innovation and efficiency, PPPs seek to optimize public service delivery and bridge infrastructure funding gaps. However, due to their long-term nature, complex contractual structures, and inherent uncertainties, PPP projects frequently encounter significant obstacles leading to suboptimal outcomes or total failure. Therefore, the success of these projects is always associated with greater complexity than traditional procurement methods (such as Design-Bid-Build or Design-Build) and understanding the factors influencing PPP Project success is also more difficult. Many failures derive from a lack of comprehensive knowledge regarding the multifaceted factors that drive project success. While previous studies have identified various Critical Success Factors (CSFs), most existing frameworks remain fragmented, focusing on either specific geographical regions, narrow stakeholder perspectives, or limited project phases. Existing literature often overlooks the crucial "soft" relational aspects, such as mutual trust, empathy, and collaborative governance, which are essential for maintaining long-term contractual harmony. Furthermore, most frameworks focus on a "Win-Win" relationship between the government and the investor, frequently neglecting the "social legitimacy" and public acceptance required for sustainability. The objective of this study is to bridge this knowledge gap by developing a comprehensive conceptual framework of CSFs for PPP projects. By synthesizing existing global knowledge, this study aims to provide a strategic roadmap with a 360-degree perspective for the project life cycle, ensuring that the needs of the public sector, private investors, and society are balanced. The study develops a comprehensive seven-dimensional conceptual framework comprising 25 thematic clusters of PPP critical success factors by employing a rigorous systematic literature review (SLR) combined with narrative analysis. The research followed a meticulous multi-stage process: (1) Identification of 1384 initial studies through major scientific databases, including Scopus and Google Scholar, covering the period from 2005 to 2025. (2) Systematic filtering based on quality criteria and direct relevance, resulting in a final sample of 111 high-quality papers. (3) Extraction of 1490 raw CSFs from the selected literature. (4) Repetitive process of qualitative coding and content analysis to merge synonymous terms and eliminate redundant factors. The synthesis process involved repeated conceptual labeling, semantic comparison, elimination of synonymous expressions, and refinement of overlapping concepts to establish a standardized vocabulary for subsequent thematic analysis. For instance, terms like "equitable risk sharing" and "optimal risk allocation" were consolidated into a single unit, while distinct concepts like "private partner financial capability" and "access to financial markets" were kept independent to maintain conceptual precision. The analysis resulted in the categorization of factors into 25 distinct thematic clusters organized into a "7-Dimensional Framework" (The 7Ps): Partnership, People, Policy, Private, Process, Project, and Public. The "Partnership" dimension focuses on relational governance, while "People" highlights social legitimacy. "Policy" refers to the enabling institutional environment, "Private" and "Public" address the internal capacities of the partners, and "Process" and "Project" cover the operational and technical feasibility. Statistical frequency analysis revealed that the top three clusters - "Feasibility Studies and Comprehensive Business Plans" (133 factors), "Macroeconomic Stability and Mature Financial Markets" (125 factors), and "Transparent and Competitive Bidding Processes" (99 factors) - emerged as the most frequently reported drivers of success. The high ranking of feasibility studies emphasizes that project success is determined during the preparation phase; without accurate demand forecasting and technical assessment, even the most capable partners cannot save a project from failure. Similarly, the importance of macroeconomic stability reflects the sensitivity of long-term investments to inflation and currency fluctuations. Notably, the emergence of "Social Support and Public Acceptance" as a top-tier cluster (76 factors) reflects the increasing emphasis on social sustainability in recent PPP research. Without public legitimacy, projects face resistance and protests that can lead to complete termination. The proposed framework offers a significant contribution to PPP theory and practice by integrating "Hard Factors" like legal frameworks and technical capabilities with "Soft Factors" like trust, commitment, and transparency. By establishing the "People" dimension as an independent pillar, the framework supports a broader perspective that extends the traditional "Win-Win" (Public-Private) model to a "Win-Win-Win" (Public-Private-People) paradigm. This study demonstrates that PPP success is a multidimensional phenomenon resulting from the interaction of institutional, relational, social, and operational factors. The 7P framework serves as a strategic "backbone" rather than a mere list of factors, providing a roadmap for practitioners to navigate the project lifecycle from inception to transfer (project preparation, procurement, financing, construction, operation, contract management, and long-term partnership governance). This framework provides a structured basis for evaluating, planning, and managing PPP projects while supporting future empirical and decision-making studies.