The report of the 20th National Congress of the Communist Party of China states, “We should adhere to sustainable development, unswervingly follow a civilized development path that is environmentally friendly, and achieve the sustainable development of the Chinese nation.” Corporate ESG performance, as an evaluation framework assessing environmental (E), social (S), and governance (G) dimensions of enterprises, aims to chart a course for enterprise growth that is environmentally sustainable, socially harmonious, and governed effectively, thereby continuously advancing corporate sustainable development. As China enters the digital economy era, data has become a core driver of digital economic growth, and data assets have emerged as a strategic resource under this new paradigm, offering novel pathways to enhance corporate sustainability. How enterprises utilize and manage data assets to empower their sustainable development has thus become an urgent practical issue. Yet, few studies have examined how data assets can be leveraged to improve corporate ESG performance. This paper draws on data from CNRDS, CSMAR, WIND, and the China Urban Statistical Yearbook, and adopts the method of measuring the data assetization level of enterprises proposed by He Ying et al. (2024) to measure the data assetization level and ESG performance of enterprises. Empirical results show that data assetization significantly enhances corporate ESG performance. Mechanism tests indicate that data assetization can enhance the ESG performance of enterprises by alleviating financing constraints, promoting the upgrading of the value chain, and reducing information asymmetry. Heterogeneity analyses reveal that the positive impact of data assetization on ESG performance is more pronounced among enterprises with higher institutional ownership, state ownership, and those in high-tech and heavily polluting industries. This study contributes to the literature in two respects. First, it extends research on the economic consequences of data assetization. While empirical studies from a micro perspective on how enterprises realize the value of data assets remain limited, even fewer have focused on the link between data assetization and ESG performance. This paper theoretically and empirically analyzes the effect of data assetization on the ESG performance of enterprises, expanding the micro empirical research on the value of data assets for enterprises. Second, it enriches the research on how enterprises improve their ESG performance through internal initiatives. As ESG performance and sustainable development are increasingly recognized by society, improving the ESG performance of enterprises has become an important practical issue. This paper discovers from the internal perspective of enterprises that data assetization can be an important driver of ESG performance, and it achieves this through three paths: alleviating financing constraints, promoting the upgrading of the value chain, and reducing information asymmetry. In doing so, it unpacks the “black box” between data assetization and corporate ESG performance, offering a new perspective for enterprise to improve their ESG outcomes. This research not only helps enterprises better harness the value of data assets to implement ESG practices and foster their own sustainable development, thereby contributing a fresh perspective to the integration of the digital and real economies, but also provides policy implications for government agencies in designing differentiated policies on data assets and ESG. Such policies can offer institutional support for enterprises to leverage data assets in advancing sustainability and accelerate the development of a unified national market for data as a production factor.