Environmental, Social, and Governance (ESG) has become a powerful model that drives corporate responsibility and sustainable finance in the world. Although it has been institutionalized rather quickly, academics and practitioners are becoming more doubtful that ESG is a viable measuring tool or it is a symbolic one. This narrative critical review is a synthesis of recent literature used to assess the conceptual underpinnings, the validity of measurement, and the implications of ESG in the corporate and financial setting. Based on recent research up to 2025, the review points to three broad streams, namely: ESG as a performance measurement instrument, ESG as a market mechanism in sustainable finance, and ESG as a contentious or myth-like entity open to credibility issues. The results of the analysis show that there is a recurring methodological inconsistency, rating deviation, disclosure reliability problems, and normative ambiguities that question the effectiveness of ESG. Although ESG has been highly effective in determining capital distribution and corporate strategy, its measurement framework is still disjointed and open to greenwashing and manipulation of strategies. The article concludes that ESG is not an entirely myth or entirely sound measurement tool, but is an emerging technology in governance that needs further refinement of its methodology, harmonisation of regulations and a greater degree of assurance. Research directions are suggested in the future to increase the credibility of ESG and theoretical transparency