The long‐term import of a fundamental challenge of adolescent social development—establishing oneself as a desirable peer companion while avoiding problematic behaviors often supported within peer groups—was examined in a community sample of 184 adolescents, followed from ages 13 to 23, along with parents, peers, and romantic partners. The dialectical nature of this challenge appeared in findings that autonomy vis‐à‐vis peer influences predicted both long‐term success avoiding problematic behavior but also more difficulty establishing strong adult friendships. Conversely, being a desirable peer companion in adolescence predicted more positive adult relationships but also greater alcohol use. Adolescents who established themselves as both desirable companions and as autonomous vis‐à‐vis peers were rated as most successful by their parents at age 23.