Purpose: Maternal depression can persist beyond the immediate postpartum period and can adversely affect maternal functioning and child development. However, evidence describing long-term trajectories and multidimensional predictors remains limited. This study investigated the 7-year trajectory of maternal depressive symptoms from childbirth to when the child reached 6 years of age and identified significant predictors across child, maternal, and family domains.Methods: In total, 1,030 mothers from the Panel Study on Korean Children were included. Depressive symptoms were assessed at postpartum years 1, 3, 5, and 7 using the Kessler Depression Scale. Latent growth modeling was used to examine symptom trajectories, and logistic regression analyses were conducted to identify predictors of depressive-symptom risk.Results: Overall, 55.6% of mothers experienced at least one episode of mild-to-moderate or severe depressive symptoms. Among at-risk mothers, depressive symptoms demonstrated a slight upward trajectory with significant individual variability (linear model fit: χ²=12.65, root mean square error of approximation=.052, comparative fit index=.961). Significant predictors included preterm or low-birth-weight delivery (odds ratio [OR]=2.29), prenatal depression (OR=2.61), postpartum depression at 1 month (OR=3.41), high parenting stress (OR=1.63), low self-esteem (OR=2.33), and marital conflict (OR=2.02). Higher educational attainment emerged as a protective factor (OR=0.59).Conclusion: These findings demonstrate the persistence of maternal depressive symptoms and highlight key predictors for promptly identifying mothers at elevated risk. Integrating routine longitudinal screening with interventions targeting maternal stress, self-esteem, and family functioning may be critical for mitigating long-term depressive trajectories. Family-centered approaches, including partner involvement and conflict-management strategies, appear essential for improving maternal mental health and promoting healthier developmental environments for children.