Abstract Across the life span, friendship is an important component of people’s support networks. This article explores the developmental roots of adult friendship intimacy and satisfaction, taking into consideration the early interplay between sociomoral sensitivity in friendship, insecurity in peer contexts, and peer rejection. Data (N = 176) came from the longitudinal study “Individual Development and Social Structure.” Respondents were surveyed repeatedly from age 7 to 37 years. Autoregressive cross-lagged panel models show that sociomoral sensitivity in friendship protects adolescents from peer rejection and is reciprocally associated with insecurity. Childhood and adolescent sociomoral sensitivity antecede early adult friendship intimacy, which, in turn, antecedes friendship satisfaction in mid-adulthood. The findings indicate a sequence of pathways from sociomoral sensitivity developed early in life to friendship quality in adulthood.