This study examined how family context at age 18 (parent-adolescent conflict, parental support, parent education) predicted between-person variation in subjective well-being (SWB; depressive symptoms and self-esteem) trajectories from age 18 to 50 years. Timing of leaving home, getting married, and becoming a parent were explored as life transitions linking family context to within-person variation in SWB. The sample consisted of 604 participants residing in a western Canadian city at age 18 (50% female; 15% with non-White ethnic origin; 29% had at least one university-educated parent) and tracked for up to 32 years. Results of conditional latent curve models with structured residuals revealed that, amid a general increase in SWB from adolescence into midlife, those with lower parent-adolescent conflict and higher parent support had higher SWB at age 18, a between-person difference largely maintained to age 50. Parents' higher education also predicted higher self-esteem, sustained into midlife. Across analyses, transition timing inconsistently predicted within-person fluctuations in SWB, with on-time transitions associated with better than typical SWB. The most robust predictors of SWB at the within-person level were marital and parental status; getting married and becoming a parent were associated with better than typical SWB at ages 25, 43, and 50 years. Family context variables were generally not associated with transition timing, and there were no indirect associations from family context to within-person variation in SWB. Results suggest that family context influences one's well-being trajectory, but forming one's own family results in positive deviations from that path.