This paper empirically examines the short- and long-term causal effects of club activities at junior high schools on students' cognitive and non-cognitive skills and their educational, labor market, and health outcomes. We aim to address the endogeneity problem of students' participation in club activities by exploring instrumental variables (IVs). As IVs, we use a school-specific policy on whether students were required to be just a member of, or actively engage in, school clubs at the public junior high schools that they attended. First, using OLS estimation, we find that 17 out of 21 skills/outcomes are significantly correlated with their participation in school club activities. However, when we instrument students' participation in school club activities, most of those skills/outcomes turn insignificant. In contrast, some significant effects are found. In the short term, school club activities improve students' academic achievement in ninth grade and reduce tardiness and absence in high school. In the long term, while school club activities significantly increase the degree of agreeableness, they decrease the extroversion and lower wages. The results of adverse long-term effects suggest that when schools intervene in students' rational choice to take no part in club activities, their involuntary participation could result in lowering their non-cognitive skill and their long-term outcomes. It can be interpreted as an inefficient allocation of resources for individual students and further undesirable results on teachers, schools and governments who should bear the cost of the club activities.