Social media have allowed public policies to be widely shared between governments and publics. South Korea is one of the leading countries in this e-government effort. Through the uses and gratifications perspective and theory of reasoned action, this study identified Korean publics’ motivations for sharing public policy promotions on social media and examined how they are related to their affective and behavioral responses. In Study 1, two separate online surveys with 1,200 and 500 Korean adults were conducted, respectively. An exploratory factor analysis was performed with the first survey and identified five motivations: philanthropism, social participation, social status, pursuing correct information, and informative values. In Study 2, another online survey with 1,000 Korean adults was conducted to test the relationships between the five motivations and attitudes, subjective norms, and behavioral intention related to sharing public policy promotions. The results indicated that philanthropism and social status were positively related to attitudes, and social status and pursuing correct information were positively related to subjective norms. Additionally, both attitudes and subjective norms were positively related to behavioral intention. This study can provide implications for governments to use social media as multidirectional channel to better promote public policies.