Certified child life specialists (CCLS) serve as an integral component of the health care team by attending to the psychosocial concerns that arise as children and their families face stressful situations. The CCLS provides individualized care to meet the developmental needs of infants, children, teens, and young adults and assists in coping with medical-related stressors, using play as a main healing modality. As they engage, assess, and educate, CCLS use play for therapeutic purposes and provide education to children and their families regarding diagnosis, treatments, procedures or tests needed, strategies for coping and managing pain, and the medical environment. In this article, two theories and one process that help guide the work of the CCLS are applied in a scenario: Bronfenbrenner's bioecological theory of human development (Bronfenbrenner, 2005), Lazarus and Folkman's (1984) transactional theory of stress and coping, and the APIE process (Wilson et al., 2006). CCLS use theory to assess, plan, and provide appropriate interventions to promote optimal care of patients.