The current study examined the social media rule implemented by Korean Baseball Organization (KBO). Domestic and international professional sport governing bodies are constantly creating and using several social media outlets in order to build a strong relationship with their fans, promote the sport and events with popularity, and share current information and news regarding the teams and players. However, it seems that there is no great support and understanding on the use of the professional athletes’ social media and its benefits. Through a comparative analysis of current social media rules adopted by KBO and other international professional sport leagues such as Major League Baseball (MLB) and other major professional sports leagues, the current study provided both recommendations for social media rule development in professional sport leagues and the necessity of realizing the importance of the use of social media and changes in perception regarding social media. Concretely, teams in professional sport teams should start to create their own culture within social media. By combining both qualitative and quantitative studies on the use of different social media platforms by KBO teams, the overall patterns of users can be evaluated. As part of desirable social media culture, engaging in social media should be the first means of communication for fans to follow their favorite sport, teams and athletes. The current study contributes to an understanding of the establishment of distinct social media rule and its correct position within professional sport leagues, teams, and athletes. It is essential that professional sport leagues need concrete rules on social media, social media channels specific training for participants, and finally the participants’ changes in understanding towards social media. The current study also recommends the tactical and active use of social media by the teams and athletes. Thereby, the authors of the current study expect Korean professional sport leagues to be continually loved by their fans and prospective fans.