Previous studies have established that individual characteristics such as violent behavior, substance use, and high-risk sexual behavior, as well as negative relationships with parents and friends, are all risk factors for intimate partner violence (IPV). In this longitudinal prospective study, we investigated whether violent behavior, substance use, and high-risk sexual behavior in early adulthood (ages 22–23 years) mediated the link between family conflict and coercive relationship talk with friends in adolescence (ages 16–17 years) and dyadic IPV in adulthood (ages 28–30 years). A total of 998 individuals participated in multimethod assessments, including observations of interactions with parents and friends. Data from multiple reporters were used for variables of interest including court records, parental and self-reports of violence, self-reports of high-sexual-risk behaviors and substance use, and self- and romantic partner-reports of IPV. Longitudinal mediation analyses showed that violent behavior during early adulthood mediated the link between coercive relationship talk with friends in adolescence and dyadic IPV in adulthood. No other mediation paths were found and there was no evidence of gender differences. Results are discussed with attention to the interpersonal socialization processes by which IPV emerges relative to individual risk factors.