For new fathers, parenting stress is a risk factor for impaired early parenting and child maltreatment perpetration. Predictors of parenting stress, including fathers’ own experiences of trauma, could be useful intervention targets to support new fathers. We aim to examine associations between new fathers’ own histories of child maltreatment, and their perinatal mental health, relationships, and parenting stress. We recruited 298 first-time fathers for a survey that measured child maltreatment history, trauma sequelae including posttraumatic stress disorder (PTSD), major depressive disorder (MDD), interpersonal reactivity, substance use, anger expression, coparenting quality, and parenting stress. On the Parenting Stress Index (PSI) (from 36 to 180), bivariate analysis demonstrated that new fathers who experienced child maltreatment (n = 94) had significantly higher parenting stress (x̅ = 85.3, σ = 18.7) than those who did not (n = 204; x̅ = 76.0, σ = 16.6; P < .000). Hierarchical linear regression modeling indicated that a child maltreatment history, PTSD, and MDD were significantly associated with parenting stress. The strongest predictors of parenting stress were coparenting quality and complex trauma sequelae—interpersonal reactivity and anger expression. Interventions to reduce fathers’ parenting stress by targeting known mental health and relationship sequelae of maltreatment are promising avenues to breaking intergenerational transmission of child maltreatment and psychiatric vulnerability.