Preschool teachers play a crucial role in facilitating children's cognitive and social-emotional development, and their ability to do so can be influenced by their professional identity. However, adverse childhood experiences (ACEs) may have impacted the professional identity of preschool teachers, a topic that has been explored by little research. To address this research gap, this longitudinal study examined the impact of ACEs on the professional identity of Chinese preservice preschool teachers. Data were collected in three waves from a sample of 591 preservice preschool teachers using self-report measures. Results from the mediation analysis showed that ACEs negatively predicted professional identity, with this relationship being serially mediated by depressive symptoms and academic stress. These findings emphasize the significance of interventions aimed at mitigating the impact of ACEs and nurturing professional identity. Interventions should consider incorporating activities to address depressive symptoms and academic stress among college students to facilitate positive outcomes.