Sustainable tourism development has become an increasingly important strategy for peripheral regions seeking to diversify local economies while maintaining environmental and social sustainability. However, the mechanisms through which tourism contributes to sustainable regional development remain insufficiently understood, particularly in post-Soviet and resource-based regional contexts. This study examines the relationships between infrastructural resources, local community participation, regional promotion, support for agro-ecotourism, tourism development, and sustainable regional development in the North Kazakhstan region. The study further investigates the mediating role of tourism development in transmitting the effects of regional factors to broader sustainability outcomes. Primary data were collected through a questionnaire survey conducted among residents and stakeholders of the North Kazakhstan region (N = 232). The proposed conceptual model was analyzed using Partial Least Squares Structural Equation Modeling (PLS-SEM). The results demonstrate that infrastructure and regional resources (β = 0.247, p < 0.001) and local community participation (β = 0.241, p = 0.001) exert significant positive effects on tourism development. In contrast, regional promotion and support for agro-ecotourism do not show statistically significant direct effects. Tourism development demonstrates the strongest positive influence on sustainable regional development (β = 0.620, p < 0.001) and significantly mediates the relationships between infrastructural and social factors and sustainability outcomes. The study contributes to sustainable tourism literature by developing a mediation-based framework that conceptualizes tourism development as a transmission mechanism linking regional resources and community participation to long-term socio-economic sustainability. The research also expands empirical evidence from peripheral and post-Soviet regional contexts that remain underrepresented in tourism sustainability studies. The findings emphasize the strategic importance of infrastructure investment, community engagement, and integrated regional planning for achieving sustainable tourism-driven development in peripheral territories.