Extensive research shows that harsh parenting is one of the primary components responsible for adolescent substance use (Neppl et al., 2009). Lower levels of parental supervision may also be associated with alcohol use in adolescence, across gender, age, and ethnicity (Pilgrim et al., 2006). Because previous research has focused primarily on mothers, even less is known about the specific role fathers contribute to adolescent alcohol use as they transition into emerging adulthood. In the current study, participants come from a two-decade longitudinal study of focal individuals and their families followed from adolescence to adulthood (N = 451). The current report examines observed father hostility toward the adolescent and low level of father involvement reported by the father when focal youth were in early to middle adolescence (13, 15, and 16 years old). Self-reported adolescent substance use was assessed during late adolescence (age 18), as well as emerging adulthood (age 21). Harsh parenting was significantly related to late adolescent substance use (β = .18, p < .001), which was significantly associated with substance use in emerging adulthood (β = .55, p < .001). Once adolescent use was added to the model, the relationship between harsh parenting and adulthood use was no longer significant.