This study explores the influence of personality hardiness and social media fatigue on job involvement, and the moderating effect of social media fatigue. The model and hypotheses were conducted based on relevant literatures, and were tested with hierarchical regression analysis on a total of 425 online surveys on current employees. The results show that personality hardiness and its three facets: control, input and challenges have significant positive influence on job involvement. As for the moderating effect, social media fatigue moderated the relationship between personality hardiness and job involvement.