Adult maladaptive behaviors including antisocial personality disorder (ASPD) and marijuana use are major public health concerns. At the present time, there is a dearth of research showing the interrelationships among the possible predictors of adult maladaptive behaviors (i.e., ASPD and marijuana use). Therefore, the current study examines the pathways from adverse family environments in late adolescence to these maladaptive behaviors in adulthood. There were 674 participants (52 % African Americans, 48 % Puerto Ricans). Sixty percent of the sample was female. Structural equation modeling in the current study included 4 waves of data collection (mean ages 19, 24, 29, and 36). An adverse family environment in late adolescence was related to greater externalizing personality in late adolescence, which in turn, was related to greater marijuana use in emerging adulthood. This in turn was positively associated with partner marijuana use in young adulthood, which in turn, was ultimately related to maladaptive behaviors in adulthood. An adverse family environment in late adolescence was also related to greater marijuana use in emerging adulthood, which in turn, was associated with an adverse relationship with one's partner in young adulthood. Such a negative partner relationship was related to maladaptive behaviors in adulthood. The findings suggest that family-focused interventions (Kumpfer and Alvarado in Am Psychol 58(6-7): 457-465, 2003) for dysfunctional families may be most helpful when they include the entire family.