Increased stress and poor sleep heighten the risk of severe health issues and impair performance and well-being. Using a mixedmethod approach, we analyzed a male head coach's stress and sleep across an international under-21 championship to assess its impact on mental well-being. The +/- 2 SD method revealed decreased sleep efficiency during and after the tournament. A semistructured interview was conducted before and after the tournament; thematic analysis was used to construct themes and subthemes. Findings showed a notable decrease in sleep duration during the tournament and an increase afterward, with a marked deterioration in sleep efficiency toward the tournament's end. Despite over 2 decades of top-level coaching experience and attending coach-education programs, the elite coach faced difficulties separating his work and personal life, adversely affecting his stress levels, sleep efficiency, and mental well-being. Posttournament, he experienced exhaustion and required 3 months for complete recovery.