Although meaningful work experience and the support of caring adults are recognized as factors that promote positive youth development, research has given minimal attention to the role of the work-based learning (WBL) supervisor. Interviews with 12 supervisors, from work sites that were identified as successful by leaders from a Catholic high school known for its high-quality work-study program for low-income adolescents, reveal that the roles, responsibilities, and relationships of WBL supervisors are complex and multifaceted. Supervisors seek to balance the goal-directed demands of managing a productive workplace with a relational commitment to teaching and mentoring young people. The results are discussed in light of relational theories of working and youth mentoring. Implications are explored for strengthening the selection and preparation of WBL supervisors who strive to enhance the life chances for low-income students of color.