Background: Staff play a critical role in promoting positive youth development in out-of-school-time programs, yet little is known about best-practices for preparing staff to work with youth and meet their needs. The present study seeks to understand the impact of a basic psychological needs training on the staff's ability to deliver needs-supportive instruction to youth during a summer wellness program. Methods: A quasi-experimental, qualitative design using interviews, observations, and journals was employed to compare the intervention staff (n = 9; M = 21.5) with a comparison group who did not receive the training (n = 8; M = 21.10). Results: Results indicated that the intervention enhanced the staff's understandings of basic psychological needs and empowered them to be more responsive to youth misbehavior, while educating youth about the importance of appropriate behavior. Conclusions: In order to prepare staff to meet the psychological needs of youth and protect themselves against exhaustion and burnout, future research should examine adequate dosage and content of staff training.