Six cardinal leadership virtues based on Aristotelian and Confucian typology were advanced through this study by developing a measurement instrument and examining its predictive validity by studying the causal association with perceived leader happiness. Based on a sample of 183 school principals engaged in various types of schools, the results of both exploratory and confirmatory factor analyses generated satisfactory empirical outcomes by finding adequate support for the overall leadership virtue scale and the constituent subscale elements. The paper concluded with the theoretical and practical implications for this developed instrument of leadership virtue especially in the context of school education. The major contribution of the paper lies in developing a measurement scale of virtues for school leaders.