A number of recent studies have examined the socioeconomic functions and side effects of environmental amenity in urban development. In this study, an urban green space is viewed as both a positive and negative environmental externality because it could be a potential contributor to gentrification. Employing the difference-in-differences method at the public use microdata areas and census-tract level, this study examines the effects of new green space characteristics on multiple gentrification indicators in New York City. Unlike previous studies, we examine the causal inference of multiple green space types and characteristics on gentrification indicators jointly, estimating a relatively short- and mid-term gentrification effect in a homogeneous institutional and geographical setting. The empirical results indicate that newly added green spaces potentially foster gentrification, influencing the replacement of the poor with wealthier inhabitants; more importantly, the gentrification effects differ depending on the type and characteristics of green spaces. A strong green gentrification effect has been observed in passive, natural and medium-sized green spaces. Taking these short-term and local-level gentrification effects of green space characteristics into consideration allows for more inclusive development and equitable outcomes.