Background: High parental education promotes various aspects of offspring well-being including reducing their risk of depression/anxiety, criminal justice involvement, and welfare reliance. However, according to minorities’ diminished returns, these benefits are not equal across racial groups, with Black families experiencing diminished returns of parental education compared to White families. This study explores the role of household income and offspring educational attainment as potential serial pathways that operate as mechanisms underlying diminished returns of parental education on offspring outcomes in Black families. Gender differences in these effects were also explored. Methods: Utilizing data from the Future of Families and Child Wellbeing Study (FFCWS) over a 22-year follow-up period (seven waves), we examined the serial mediation by household income and offspring educational attainment in explaining the relationship between parental education and offspring outcomes namely depression, anxiety, criminal justice involvement, and welfare reliance [Temporary Assistance for Needy Families (TANF) and Supplemental Nutrition Assistance Program (SNAP)]. We used structural equation modeling (SEM) with household income as the first mediator and young adult education as the second mediator. Multi-group models were used to explore gender differences in these paths. Results: The study confirmed the role of our proposed serial mediators for Blacks’ weaker effects of parental education on offspring outcomes. We observed weaker effects of first affects household income, with this effect being for Black families compared to White families, which then impacted educational attainment of the offspring. The findings indicate that household income plays a crucial mediating role, but its effect is weaker in Black families. Additionally, the educational attainment of offspring from highly educated Black parents is less effective in improving outcomes compared to their White peers, further contributing to diminished returns. Some gender differences were observed for the effects of educational attainment on economic and health outcomes of young adults. Conclusions: The study underscores the need to reconsider traditional assumptions about the comparability of family conditions and outcomes across racial groups with similar levels of parental education. The findings highlight the importance of targeted policies and interventions aimed at enhancing the economic stability and educational outcomes of Black families to address these disparities. Policies should focus on promoting the economic well-being of highly educated Black parents and improving the educational outcomes of their children.