Guided by a novel analytic framework, this study investigates the developmental mechanism through which parental warmth is related to young adult depression. Data were from a large sample of participants followed from early adolescence to young adulthood (N = 1,988; 54% female). Using structural equation modeling, we estimated and compared competing developmental models – enduring effects vs. revisionist models – to assess whether parental warmth during adolescence had enduring or transient effects on depression in young adulthood. We also examined whether contemporaneous experiences of parental warmth in young adulthood were more salient than parental warmth in adolescence. Results supported the revisionist model: early intergenerational experiences in adolescence predicted psychopathology early in young adulthood, but their unique effects gradually diminished; whereas parental warmth in young adulthood continued to be protective of young adult depression. Effects of mother and father warmth on young adult depression were similar in pattern and magnitude. Results were held when accounting for covariates such as adolescent sex, family income status, and family structure. Young adult mental health interventions may consider targeting maintenance or improvement in parental warmth to help offset the long-term impact of adversity early in life.