Despite the numerous adverse consequences of exposure to parental domestic violence (PDV), some of those with a history of PDV thrive in adulthood and achieve complete mental health (CMH). This study investigates whether lifetime history of mental illness (depression, anxiety, substance use disorder) and social support (social provision scale) mediate the relationship between exposure to PDV and CMH in adulthood. A sample of 17,739 respondents from the 2012 Canadian Community Health Survey-Mental Health including 326 with a history of chronic PDV (> 10 times before age 16). CMH was defined as: 1) the absence of mental illness and substance dependence; 2) happiness or life satisfaction; and 3) psychological and social well-being. Path analyses were used to test the objective. Those exposed to PDV had a significantly lower prevalence of CMH compared to the general population (62.5% vs 76.1%, p < .001). Evidence of mediation was found for depression (indirect effect = -.19; 95%CI = -.30, -.09, p = .002), anxiety (indirect effect = -.12; 95%CI = -.20, -.05, p = .005), substance use disorder (indirect effect = -.04; 95%CI = -0.07, -.01, p = .016) and social provisions (indirect effect = -.13; 95%CI = -.19, -.07, p < .001). Among those with a history of PDV the odds of CMH were lower among those with lower social support and those with a history of substance use disorder or anxiety. It is important to consider mediators, such as mental health and social support, when addressing the negative outcomes of witnessing PDV.