Ostracism in the workplace is a common phenomenon in modern society that impairs employees’ well-being. This study suggests that workplace ostracism reduces subjective well-being by examining the effect of workplace ostracism on subjective well-being. Based on self-determination theory and resource conservation theory, this study explores the underlying processes and their contingent factors in the relationship between workplace ostracism and employee well-being. Specifically, this study hypothesizes that workplace ostracism decreases employees’ well-being by enhancing employees’ need satisfaction. Furthermore, the perception of a direct supervisor’s authentic leadership positively moderates the relationship between workplace ostracism and employees’ need satisfaction. This study used moderated mediation analysis to evaluate our predictions using a two-time online survey of 485 Korean employees. The findings revealed that workplace ostracism has a detrimental impact on employee well-being via need satisfaction. However, perceptions of a direct supervisor’s authentic leadership positively moderate the association between workplace ostracism and need satisfaction. Our results have important practical and theoretical implications in the workplace ostracism literature.