This dissertation examines low-income fathers’ involvement with their young children using the Fragile Families and Child Wellbeing (FFCW) data. Chapter 3 entitled, “He Said, She Said: Comparing Father and Mother Reports of Father Involvement,” compares mother and father reports of fathers’ frequency of involvement in various activities and in measures of emotional involvement. This chapter finds that fathers report spending 17.6 percent more time engaged in 11 activities with their young children than mothers report the father spending. How parental disagreement is measured yields starkly different results given the underlying distribution of these data. Chapter 4 entitled, “Estimating the Impact of Child Support and Welfare Policies on Fathers’ Involvement,” is a longitudinal analysis combining three waves of the FFCW data with annual, state-level policy data on child support enforcement and welfare policies. This chapter examines the impact of policies on fathers’ involvement over time. Fathers’ involvement is operationalized as accessibility, responsibility, and engagement. Using parents that are unmarried at the time of the focal child’s birth, this chapter finds that public policies do influence fathers’ involvement after controlling for individual social and demographic characteristics. Policies may be operating in conflicting ways to both increase and decrease fathers’ involvement. For example, fathers’ daily engagement is positively affected by stronger paternity establishment policies but is negatively affected by stronger child support enforcement collection rates and the welfare family cap policy. Chapter 5 entitled, “Two Dads Are Better Than One: Biological and Social Father Involvement,” examines whether biological and social fathers are substitutes or complements in a child’s life and how biological fathers and social fathers impact the mother’s frequency of involvement. This chapter finds that resident social fathers contribute as much time to the focal child as resident biological fathers. Factors that increase the overall parental frequency of involvement include having: a resident biological or social father, native-born parents, a biological father who had a very involved father, and a positive relationship between the biological parents. Factors that decrease overall parental frequency of involvement include: the father’s new partner, the father’s incarceration, a mother’s other children, and the child’s increasing age. / text