Men’s family formation patterns have changed in recent decades. Fewer men, for example, experience marriage during young adulthood, and the transition to fatherhood before marriage has become more common for contemporary cohorts. At the same time, young men’s socioeconomic opportunities have also shifted. These concurrent changes bring into question the extent to which shifts in family formation trends are a result of shifts in men’s experiences during young adulthood. Using thirty rounds of interviews from the National Longitudinal Surveys of Youth 1979 and 1997, this study examines whether cohort differences in men’s entry into premarital fatherhood are explained by changing participation in four institutions (school enrollment, employment, active military service, and incarceration) and in premarital cohabitation. Given the widening levels of inequality, it is crucial to have a strong understanding of the ways these institutions can place disadvantaged youth on a pathway towards improved outcomes in later life.