PurposeThis study aimed to determine the impact of job fitness on depression and depressive symptoms in Korean middle-aged and older population.MethodsWe collected data from the Korean Longitudinal Study of Aging (KLoSA), and performed a longitudinal analysis on 3,185 individuals with jobs at baseline. The dependent variable, depressive symptoms was measured by CES-D10 score, and the main variable of interest, job fitness was classified into nine groups according to job satisfaction and education level. To determine whether the estimate of depressive symptoms over the past week and depression changed over time, we applied the Generalized Estimating Equation (GEE) model.ResultsIn the fully adjusted model, the impact of job fitness on depression and depressive symptoms was statistically significant. Compared to those with a suitable job level and a medium educational level, those with a large gap between job and educational levels were more likely to develop depression and depressive symptoms. It was also found that satisfaction with job content was a crucial factor affecting depression in the middle-aged and older adults.ConclusionOur findings demonstrated that job fitness significantly influenced depression, even after accounting for the effect of job satisfaction caused by a mismatch in job-education fitness. Since work demands and responsibility are difficult to quantify or qualify, job-education fitness could serve as a valuable tool to predict the extent of depression deterioration in individuals.