This study seeks to increase our understanding of the views about teacher quality put forward by leaders and teachers of highly effective schools. The paper presents findings from a mixed-methods study: Drawing on data from interviews with leaders of highly effective schools in England, we identified eight characteristics of an outstanding teacher. To date, N = 404 survey participants ranked these properties from most to least important. Comparing perspectives from highly effective and improving schools to those from averagely effective schools, our findings indicate a significantly higher importance of a teacher's focus on personal development and improvement in highly effective schools, which may lend credence to the belief that "good teachers are made, not born."