This study aims to analyze the implementation of principal's transformational leadership in strengthening character education through Scout extracurricular activities at ten public elementary schools in Wirosari District, Grobogan Regency. A mixed methods approach with sequential exploratory design was employed, combining qualitative methods (in-depth interviews, observations, and documentation) with quantitative methods (questionnaires to 200 students). Results show principals implemented transformational leadership through four dimensions: idealized influence, inspirational motivation, intellectual stimulation, and individualized consideration, with a mean score of 3.69 (high category). Hypothesis testing confirmed a positive and significant effect of transformational leadership on the effectiveness of Scout activities (t = 4.251 > t-table = 1.972; sig. 0.000 < 0.05), with the regression equation Y = 79.010 + 0.257X and R² = 8.4%. Scout activities proved effective in building students' character, particularly discipline, responsibility, leadership, cooperation, and social awareness, with a mean score of 3.92 (high category). These findings imply that principal's transformational leadership plays a strategic role in optimizing Scout extracurricular activities as a medium for sustainable character education.