This study aims to explore the impact of Environmental, Social, and Governance (ESG) performance on the financial performance of firms in China’s high-tech and internet industries. Using annual data from 100 companies spanning from 2015 to 2022, a fixed effects model is applied for empirical analysis. The study finds that overall ESG performance has a significant positive impact on firms' return on assets (ROA) and net profit margin (NPM), with the governance (G) and social (S) dimensions showing particularly strong effects. While the environmental (E) dimension has a weaker short-term impact on financial performance, its long-term benefits are undeniable. Firm size and market share also have significant positive effects on financial performance. The results suggest that optimizing governance structures and actively fulfilling social responsibilities can enhance financial performance, while long-term investments in environmental responsibility should be integrated into corporate strategies. Overall, the findings provide empirical evidence for companies in formulating ESG strategies and offer specific policy recommendations for the sustainable development of China’s high-tech and internet industries.