PurposeThe empirical paper aimed to develop a theoretical model of social capital in professional spectating sports by investigating the antecedents and outcomes related to social capital from the spectator’s viewpoint.Participant and MethodBrothers Elephants, a professional baseball franchise in the Chinese Professional Baseball League, provided the research setting. The study’s participants consisted of 422 spectators of a Brothers Elephants game at its home field, Taichung Intercontinental Baseball Field. Around half of the participants were male; 46.4% of them aged between 30 and 39 years old. Data analysis was conducted through structural equation modeling.ResultsResults revealed that social interactions positively correlated with social capital, prosocial behavior, and spectator intention to re-attend the sporting event. Corporate social responsibility (CSR) also positively predicted intention to re-attend the sporting event, social capital, and prosocial behavior. Social capital significantly correlated with prosocial behavior and subjective well-being, and prosocial behavior significantly correlated with subjective well-being and intention to re-attend the sporting event.ConclusionThe results suggest that social capital can be developed through social interactions and perceived CSR in the context of professional spectator sporting events, with such social capital increasing, in turn, prosocial behavior, subjective well-being, and intention to re-attend the sporting event. From perspective of practical implication, professional sports franchise can develop more campaigns that boost sports spectators’ perceived social interactions and CSR, which can increase their social capital, prosocial behavior, subjective well-being, and their intention to re-attend the sporting event.