This study explores the mechanism of expanding fan engagement through the official YouTube channels of professional baseball teams by examining the effects of YouTube watching motivationon spectator intention, and verifying the roles of mediating variables. Using PROCESS macro Model 6, a structural pathway was analyzed in which watching satisfaction, continuous watching intention, and player imageserve as mediators. The analysis revealed that while YouTube watching motivation did not directly influence spectator intention, six indirect effects through the mediators were statistically significant. In particular, the triple mediation effect, where watching motivation sequentially influences spectator intention via the three mediators, was found to be significant. These results empirically demonstrate that digital content consumption goes beyond a simple viewing experience—it enhances satisfaction, encourages continued engagement, and shapes favorable player images, ultimately leading to actual spectator behavior. This study provides strategic implications for KBO teams in developing content strategies that utilize YouTube to strengthen fan loyalty and promote game attendance.