This study uses worker-level longitudinal panel data and trade data to conduct an analysis of the performance of Korea's employment insurance system in supporting trade-affected workers. We find that the rapid economic growth of China and Vietnam since the 2000s has subjected some Korean industries to heightened import competition. The Korean workers who were employed in these industries in their earlier careers tended to experience a long-term (10-year) decline in the growth rate of labor income and a relative deterioration in their employment security as the probability of involuntary job separation increased. With an increased probability of involuntary job separation, workers in import-competing industries were more likely to receive unemployment benefits. This implies that the unemployment benefit system in Korea was relatively effective in the short term to alleviate employment shocks triggered by trade shocks. Nevertheless, the trade adjustment support function of the unemployment benefit system had certain limitations in that the receipt of unemployment benefits could not ultimately counteract the downward trend in long-term labor income for workers in import-competing industries. In contrast to unemployment benefits, government-supported vocational training holds the potential to increase the long-term earnings of workers more exposed to import competition. However, workers employed in import-competing industries were not more likely to participate in government-supported vocational training; on the contrary, workers in export-expanding industries were more likely to participate in government-supported vocational training. This finding implies that the jobs of workers in import-intensive industries were less likely to be covered by employment insurance than those in export-intensive industries. Consequently, workers in import-intensive industries, who are at greater risk of trade shocks, may be less safeguarded than their counterparts in export-growing industries under the prevailing employment insurance system.