Exceptionally high rates of partner violence perpetration are evident among men returning from prison. Two bodies of scholarship, one on family stress and another on exposure to state violence, each suggest that criminal legal system exposure could promote partner violence perpetration via changes in men’s behavioral health and interpersonal approach and in couples’ conflict dynamics. Such relationships have not been tested in quantitative research. Structural equation models were fitted to longitudinal, couples-based survey data from the Multi-site Family Study on Incarceration, Parenting, and Partnering. Participants included men returning from a state prison term in five U.S. states (N = 1112) and their committed intimate or co-parenting partners (N = 1112). Models tested hypothesized pathways from three dimensions of criminal legal system exposure to later partner violence perpetration. In fitted models, men’s childhood criminal legal system exposure predicts their post-prison partner violence perpetration via adult post-traumatic stress symptoms, reactivity, avoidance, and dysfunctional couple conflict dynamics. Men’s cumulative criminal legal system exposure in adulthood predicts their post-prison partner violence perpetration via addiction and dysfunctional couple conflict. These initial results suggest that mass-scale incarceration could worsen partner violence via men’s psychological and interpersonal adaptations to criminal legal system contact, particularly when such contact is sustained or occurs at a developmentally significant period in the life course.