The purpose of this study was to examine longitudinally how father involvement mediates the relationship between a variety of factors thought to influence the father-child relationship and later child cognitive development. The Responsible Fathering Framework was used as a conceptual model to test items collected in a large national data set (Early Childhood Longitudinal Study-Birth Cohort Study [ECLS-B]). Latent variables were constructed from the ECLS-B when the child was 9-months, 2-years, and 4-years among a sub sample of married resident biological fathers using exploratory and confirmatory factor analyses at multiple time points. Specifically, this study tested a model of hypothesized relationships between early father factors (role identification, commitment, education), child factors (difficult temperament, disability status, cognitive ability), mother factors (education, employment), contextual factors (religious service attendance, social engagement, urbanicity, crime rate, child poverty), marital relationship factors (relationship happiness, couple conflict) when the child was 9-months and later children’s language, literacy, and math development at 4-years of age, mediated by father involvement (cognitive and caregiving engagement, accessibility, and responsibility) when the child was 2-years old. A full measurement model was tested including both latent and observed variables, was assessed first, followed by testing of the structural model to arrive at the most parsimonious model before applying the sample weights. Results of the weighted structural equation model suggest that father involvement served as a poor mediating variable. Although a positive relationship was found between several of the factors at 9-months and later father involvement, the only relationship that was fully mediated by father involvement was the effects of mother employment on later cognitive development. Examination of the path coefficients suggest that fathers’ responsibility was negatively related to children’s later language development and that fathers’ caregiving engagement was also negatively related to children’s later literacy development. As expected, cognitive involvement was positively related to literacy development. Implications for future research and practitioners, particularly marriage and family therapists who work with families, are discussed.