Background <p>Physical activity (PA) has been associated with subjective well-being (SWB) among adolescents. However, the processes underlying this association, particularly the role of physical activity enjoyment (PAE) in PA, have been less explored. This study aimed to examine the associations among PA, PAE, and SWB among Chinese adolescents.</p> Methods <p>A cross-sectional study was conducted among 947 students recruited from two junior high school and two senior high schools in a city in Shanxi Province, China. Participants completed validated questionnaires assessing PA, PAE, and SWB. Using the SPSS macro PROCESS, a mediation model was tested with PA as the independent variable, SWB as the dependent variable, and PAE as the mediator while controlling for gender and grade. The bootstrap method was employed to examine the significance of the mediating effect.</p> Results <p>Mediation analysis revealed that PA was a significant positive predictor of both PAE (<i>β</i> = 0.529, <i>P</i> &lt; 0.001) and SWB (<i>β</i> = 0.147, <i>P</i> &lt; 0.001). However, when PAE was included in the model, the direct effect of PA on SWB became nonsignificant. Bootstrap results (based on 5000 samples) confirmed that the direct effect was not significant (<i>β</i> = -0.010, 95% <i>CI</i> [-0.039, 0.031]), whereas the indirect effect through PAE was significant (<i>β</i> = 0.157, 95% <i>CI</i> [0.110, 0.209]).</p> Conclusion <p>PAE mediates the relationship between PA and SWB in adolescents. These findings highlight the potential importance of promoting enjoyable PA experiences to support adolescent well-being.</p>