Objective: Financial hardship influences depression risk, however, the pathway of the effect of financial hardship on depression and the role of self-esteem remain unclear. This study examined whether changes in financial hardship affected depression, and whether self-esteem mediated by this relationship. Methods: Data from 99,588 observations of 15,331 individuals were extracted from 10 waves of the Korean Welfare Panel Study. The association between changes in financial hardship and depression was investigated using a generalized estimation equation, and the extent to which these associations were mediated by self-esteem was assessed. Results: The results indicated that changes in financial hardship were associated with depression, with varying magnitude. Experiencing severe financial hardship over two consecutive years (odds ratio [OR]: 3.87, 95% confidence interval [CI]=3.09–4.85) or increased financial hardship over the previous year strongly influenced depression (e.g., OR: 3.88, 95% CI=3.09–4.86 for low financial hardship at t-1 year and high at t year). Self-esteem plays a mediating role in the relationship between changes in financial hardship and depression, where persistent financial hardship is associated with low self-esteem, leading to depression. Conclusion These findings highlighted the importance of monitoring and intervention for financial hardship and psychological problems to help manage depression.