<p>This study is grounded in the dynamic relationship between governmental cultural governance (GCG) and regional social capital (RSC). What are the cultural factors behind the regional development? How do the two forces of GCG and RSC operate? How did cultural innovation become a reality? This study constructs a GCG and RSC coupling coordination index system, innovatively establishing a four-dimensional analysis framework that integrates conceptual, data, analytical, and decision-making layers. It comprehensively employs methodologies, including the coupling coordination degree model, decision trees, and questionnaire surveys, to conduct empirical examinations using decade-long (2013–2023) panel data from four Yangtze River Delta provinces. The findings indicate that Zhejiang exhibits the highest level of coordinated governance between GCG and RSC within the Yangtze River Delta region. The province’s distinctive development trajectory can be attributed to systemic support for grassroots entrepreneurship and the positive influence of regulated social capital, including risk tolerance and openness to innovation. The “moral norms and cognitive norms” of social capital have a profoundly empowering effect on the cultural governance of the Zhejiang government. Furthermore, the research indicates that if the government overly emphasizes “cultural marketization development” while lacking investment in “cultural talent” cultivation, it will hinder the accumulation of social capital. The findings not only offer further recommendations for enhancing cultural governance in Zhejiang Province but also provide valuable insights for global policymakers aiming to leverage cultural resources to foster regional development.</p>