In this study, the mediator and moderator effects of subjective vitality on the relationship between life satisfaction and subjective happiness were investigated. The participants were 378 university students who completed a questionnaire package that included the Subjective Vitality Scale, the Satisfaction with Life Scale, and the Subjective Happiness Scale. The results of hierarchical regression analysis demonstrated that subjective vitality partially mediated the relationship between life satisfaction and subjective happiness. Hierarchical regression analysis indicated that subjective vitality did not moderate the relationship between life satisfaction and subjective happiness.