<p>Sport has gained attention as a potentially useful intervention for recovery and well-being among people with psychiatric disorders. However, there is existing concern among practitioners whether sport exacerbates clinical outcomes. The purpose of the current study was to examine whether and how participation in sport is associated with positive psychosocial outcomes. This study focused on football activities that has been organized mainly for people with psychiatric disorders in Japan, called Social Football, and a total of 88 players participated in an online survey. Participants were asked to compare the status of medication amount, sleep quality, speed of thought, and engagement in social activity between now and before they began playing Social Football for the first time. Additionally, subjective well-being, athletic identity, serious leisure, activity enjoyment, perceived social connectedness through Social Football, depressive symptoms, and loneliness were measured. The participants generally perceived reduced medication amount, better sleep quality, faster speed of thought, and increased engagement in social activity since they began engaging in sport. In addition, results indicated that perceived social connectedness in sport and loneliness were significant predictors of subjective well-being after other variables were statistically controlled. While the results must be interpreted with caution due to the potential for selection bias, the results may suggest that facilitating greater opportunities to establish social relationships with others is important for players’ subjective well-being.</p>