As the population ages rapidly, there is a strong focus on the healthy aging of older adults. A central part of healthy aging is keeping people connected in later social life. Exergames are recommended as one of the coping strategies to help improve health and quality of life in older adults. In our study, we developed an exergame called Social Balance Ball to engage older and younger people to play together, encouraging social interaction between generations. From May to July 2021, we evaluated this exergame in Shanghai, China, performing a user experiment with 18 unfamiliar young-old pairs under three test conditions (virtual player, mediated human player, and o-located human player). To evaluate the exergame, our main findings demonstrated that participants felt significantly perceived social interaction in mediated play and co-located play than in virtual play. Overall, older participants perceived significantly higher social interaction than younger participants. In this study, we contribute (1) empirical research findings on how the SocialBalance Ball exergame enhances social interaction in generations; (2) design implications for informing future design and development of social exergames