Youth who are most vulnerable to challenging community conditions, more limited opportunities and poor health, educational and economic trajectories derive especially strong benefits from engagement in community youth development efforts (Gambone, Yu, et al. 2004). Like many community youth development efforts, the REACH Youth Program called upon grantees to address the needs of all youth. While grantees were selected to reflect the diversity of communities in the region and were encouraged to recruit youth reflecting the diversity within those communities, they were not asked in particular to reach out to their most vulnerable youth populations. Across REACH, involvement of previously un/underengaged youth was limited, albeit with important variation across places and times. Grantees that did engage such youth over time offer important lessons about how to create the types of safe, supportive and meaningful settings that promoted young people's ongoing participation and leadership. Key elements of their success included: (1) Intentionality and Commitment; (2) Local Knowledge of Vulnerable Populations; (3) Adult Allies with Key Capacities; (4) Meaningful Focus; (5) Resources for Intensive Outreach, Relationship-building and Youth Support; and (6) Continuity of Key Adults. This brief describes each of these elements and offers some overarching lessons learned about engaging vulnerable youth populations in community youth development. Examples are drawn from two grantees that tapped the knowledge and insights of underrepresented youth over an extended period of time. [This paper was written with Lisceth Cruz Carrasco and David Campbell.]