In the realm of tourism intervention and the reconfiguration of social networks among residents in ethnic villages, research on tourism support behavior is pivotal for comprehending the motivations behind resident participation and fostering sustainable tourism development. This study carried out a survey of 440 residents from Huangluo Yao Village and Jinkeng Dazhai Village in Longsheng County, Guilin City, Guangxi Zhuang Autonomous Region, China, using a questionnaire and explored the influencing mechanism of social networks on tourism support behavior based on the cognitive–affective processing system (CAPS) theory using structural equation modeling (SEM). The findings reveal that both strong and weak ties exert direct impacts on tourism support behavior while also indirectly influencing it via cultural identity. Furthermore, government governance capacity serves as a positive moderating factor in the relationships between ethnic village residents’ social networks—both strong and weak—and cultural identity, as well as between weak ties and tourism support behavior. The conclusions drawn from this study not only enhance the understanding of the formation mechanisms underlying tourism support behavior but also offer valuable insights for local governments aiming to implement effective strategies to promote tourism development.