The present study examined the effects of personal-disclosure mutual-sharing (PDMS) on a diverse set of group factors in a previously unexplored context. During a single bout of PDMS, 14 soccer-academy athletes voluntarily disclosed unknown personal stories to fellow teammates. Social identity, friendships identity content, results identity content, and collective efficacy were measured at baseline, post-PDMS, follow-up, and maintenance phases. In addition, team performance over the competitive season was assessed via goal difference and goal discrepancy. Data indicated that a short-term significant increase in friendships identity content and a sustained improvement in team performance occurred after the PDMS session, and social identity, results identity content, and collective efficacy remained elevated across all intervention phases. Data suggest that PDMS fosters immediate increases in aspects of team functioning that may exert a positive influence upon team performance. Future research would benefit from ascertaining the exact mechanisms in which PDMS encourages changes in team outcomes observed within the current study.