Learning initiative is a critical foundation for young children’s long-term learning engagement. Existing research has predominantly viewed it as an individual trait, with limited focus on interactional mechanisms in daily educational contexts. This qualitative study explores how adult support shapes children’s learning initiative in early childhood education settings. Drawing on classroom observations, semi-structured interviews, and parent questionnaires, the findings identify three core mechanisms: adult verbal encouragement as an immediate trigger, emotional safety as a mediating condition for sustained engagement, and home–school alignment as a reinforcing factor. By reconceptualizing learning initiative as an interactionally constructed process, this study advances sociocultural and autonomy-supportive perspectives, offering practical insights for educators and parents.