This paper draws on information from the Fragile Families Study (N = 2,695) to examine how different coparenting styles emerge and are related to fathers' involvement with young children in a representative sample of unmarried parents. The results show that the quantity and quality of paternal involvement is significantly higher when unmarried parents establish a cooperative as opposed to a disengaged or conflicted coparenting style. Cooperative coparenting is less likely, however, when unmarried parents have separated after the birth or were never together as a couple, when fathers are unemployed or have other risk factors, when the child has a more difficult temperament, and when parents have fewer children together. This analysis also helps clarify previously equivocal findings concerning the relationship between coparenting conflict and paternal involvement. Regression results show that paternal involvement is not significantly different among parents with cooperative and mixed coparenting styles, indicating that when unmarried parents can work together and support each other's parenting efforts, even if they argue frequently while doing so, fathers remain more involved. At the same time, conflicted coparenting leads to a larger decrease in father involvement than disengaged coparenting. In the context of poorer-quality coparenting relationships, it was conflict that mattered for fathering, not just parents' inability to cooperate. Implications of these findings for parenting education programs are discussed.