Background: Environmental, Social, and Governance (ESG) criteria have emerged as critical determinants of corporate sustainability and long-term financial performance, particularly within the technology-intensive Indian information technology (IT) sector. Objectives: This study empirically investigates the relationship between ESG performance dimensions and corporate sustainability outcomes among Nifty IT-listed companies over the period 2019-2024. Methodology: Employing a balanced panel dataset of 30 Indian IT companies across 180 firm-year observations, the study applies fixed-effects panel regression, random-effects models, and the Generalised Method of Moments (GMM) to address endogeneity concerns. Findings: Results indicate a statistically significant positive relationship between composite ESG scores and all financial performance metrics (p < 0.01). The governance pillar exhibits the strongest explanatory power (beta = 0.412), followed by environmental (beta = 0.318) and social pillars (beta = 0.267). Firm size and R&D intensity moderate the ESG-performance nexus. Conclusion: Proactive ESG adoption creates sustainable competitive advantage for Indian IT companies, with significant implications for regulators, institutional investors, and corporate boards.