This study examined the typology of depressed mood trajectories and the associated factors over the first year postpartum among Taiwanese mothers. Data of 4332 mothers from a nationwide longitudinal study on child development and care were analyzed. Three classes of depressed mood trajectories were identified, two with lower initial scores and a decreasing trajectory and one with a higher initial score and an increasing trajectory. Subjective financial stress, perceived support, and marital satisfaction were significant in predicting mothers’ membership of the depressed mood trajectory classes. The results highlighted the individual susceptibility to the postpartum depressed mood among Taiwanese mothers.