The 2030 Agenda highlights education and entrepreneurship as critical drivers of sustainable development, yet little is known about how sustainability literacy translates into green entrepreneurial confidence among Gen Z students in developing and post-conflict economies. This study examines the direct and mediated effects of sustainability literacy on green entrepreneurial self-efficacy (GESE) through biospheric values, and the moderating roles of university support, digital literacy, and family support. A cross-sectional survey was conducted with 417 Gen Z undergraduate students from Universitas Negeri Padang (Indonesia) and Universidade Nacional Timor Lorosa’e (Timor-Leste). Data were analyzed using PLS-SEM and Importance-Performance Map Analysis (IPMA). Results show that sustainability literacy directly enhances GESE (β = 0.342, p < 0.001) and indirectly through biospheric values (indirect effect = 0.156, p < 0.001). University support moderates the values→efficacy pathway (β = 0.148, p < 0.05), while digital literacy moderates the literacy→efficacy pathway (β = 0.198, p < 0.01). However, family support did not moderate any relationship, and digital literacy exhibited a ceiling effect among Gen Z respondents. IPMA reveals biospheric values and sustainability literacy as high-importance, high-performance priorities, with no urgent intervention needed. We conclude that cultivating biospheric values matters more than transmitting knowledge alone, and university support should strategically target value-driven students rather than compensate for low literacy.