This study explored directions for enhancing the intervention competencies of staff at disability welfare institutions in supporting adults with developmental disabilities who exhibit challenging behaviors. Focus group interviews (FGIs) were conducted with Disability Welfare Institute staff, and the results of the analysis are as follows. First, the challenging behaviors of adults with developmental disabilities were characterized by sensory sensitivity, limited emotional expression, and restricted forms of communication, and were accompanied by difficulties in identifying the functions of these behaviors as well as ethical and practical constraints. Second, trust-based relationships and strategy sharing contributed to successful interventions, while interpretational differences and inconsistency hindered them. Third, participants emphasized the need for disability awareness, egalitarian relationships, and collaboration, along with support systems such as manuals, team-based training, and long-term consultation. Requests were also made for staffing based on severity and for environmental adjustments. Fourth, repeated exposure to challenging behaviors, heavy workloads, and caregiver expectations contributed to burnout, while positive interactions, rest, flexible work schedules, substitute personnel, and institutional support promoted recovery. Based on these findings, this study suggests practical directions and implications for future research.