<p>Against the backdrop of digital economy expansion and mounting green transformation pressure, how digital investment drives cross-organizational green upgrading has become a central issue in supply chain governance. Integrating agency structure theory and embedded governance theory, this study examines whether enterprises’ digital investment promotes supplier green transformation. Using data from listed firms in China’s A-share electronic information manufacturing sector from 2010 to 2024, this study finds that digital investment significantly enhances supplier green transformation through collaborative and financial mechanisms, generating green spillover effects along the supply chain. This effect is more pronounced among non-state-owned enterprises, enterprises with older management teams, higher ownership concentration, greater customer concentration, and those located in regions with stronger market development and better digital infrastructure. Further analysis shows that suppliers’ digital investment does not significantly improve clients’ green transformation, suggesting asymmetric spillover effects, which can be alleviated by reputation and information effects. This study enriches research on digital governance, green supply chain collaboration, and cross-enterprise green transformation.</p>