<p>Despite growing research on children’s digital media use, existing studies have primarily examined the individual effects of home digital resources and parent–child digital interactions on developmental outcomes. However, relatively little is known about how these factors operate together within the home digital environment or about the mechanisms through which they contribute to preschoolers’ digital literacy development In particular, little is known about whether the mechanisms linking home digital environments to digital literacy function in distinct ways across operational and cultural dimensions. Likewise, the distinct role of maternal verbal interaction beyond shared digital co-use remains poorly understood. Drawing on the Techno-Subsystem framework, this study examined the mechanisms through which the home digital environment influences preschoolers’ digital literacy, focusing on the differentiated role of maternal verbal interaction in the relationship between digital co-use and preschoolers’ digital literacy. In contrast to prior studies, this study differentiates digital literacy into operational and cultural dimensions to examine potentially distinct developmental mechanisms. Data were collected from 514 Korean mothers of children aged 5 and analyzed using a serial mediation model. Results revealed that home digital resources had significant direct effects on both operational and cultural digital literacy. However, the mediating mechanisms differed across dimensions. Moreover, maternal verbal interaction — both independently and as part of a sequential pathway following digital co-use—significantly mediated the relationship between home digital resources and operational digital literacy. In contrast, none of the indirect pathways reached significance for cultural digital literacy, suggesting that the developmental processes underlying operational and cultural dimensions may differ. These findings suggest that while maternal verbal interaction supports the acquisition of basic digital skills, the development of cultural digital literacy may require broader forms of engagement and participation in socially meaningful digital practices. This study contributes to the field by clarifying how home digital resources, digital co-use, and maternal verbal interaction contribute differently to operational and cultural digital literacy in early childhood. The findings underscore the importance of both home digital resources and diverse parent–child verbal interaction in supporting preschoolers’ digital literacy development. They further highlight the need for culturally responsive parent education and policy strategies that promote intentional and developmentally appropriate media engagement in the home, moving beyond mere shared device use toward interactional practices that support children’s active participation and meaning-making during digital experiences.</p>