This study investigates how digital infrastructure contributes to smart city performance in emerging economy contexts, and whether its impact is shaped by governance models.We estimate the effect of a Digital Technology Index on a composite Smart City Index, employing a generalized least squares (GLS) random-effects model to address heteroskedasticity and serial correlation. The analysis reveals a robust and statistically significant relationship: a one-standard-deviation increase in digital infrastructure corresponds to a 0.7-standard-deviation rise in smart city performance with a potential evidence of diminishing returns at higher levels of digital maturity. To interpret these results, we draw on a qualitative case study of Wang Chan Valley (WCV), a science and innovation hub in Thailand’s Eastern Economic Corridor. WCV exemplifies how early-stage digital investment can amplify smart development outcomes and generate spillover effects across the broader urban region [1,4]. The case reinforces our hypothesis that digital infrastructure embedded within participatory innovation ecosystems yields greater and more sustainable smart city gains than technology investment alone. Taken together, our findings contribute to the literature by integrating econometric evidence with governance-sensitive perspectives on smart urban transformation in emerging economies.