This study explores the impact of Environmental, Social, and Governance (ESG) integration on the financial performance of investment portfolios (FPIP). Analyzing global perspectives from financial professionals, the research identifies a positive relationship between ESG criteria (IESGC) and portfolio performance. Through regression and correlation analyses, it is found that 53% of portfolio performance variation can be attributed to ESG strategies. Regulatory frameworks (RF) are shown to moderate this relationship, enhancing ESG effectiveness across regions. Regional variations (RV) also significantly influence how ESG factors are prioritized, leading to different financial outcomes. Despite limitations like potential self-reporting biases and the evolving nature of ESG criteria, the study underscores the importance of ESG integration for improving portfolio performance, particularly in supportive regulatory environments. This research contributes to sustainable finance literature, offering insights for investors, policymakers, and financial institutions aiming to balance profitability with sustainable development goals. Future studies could explore the long-term market impact of emerging ESG trends