This study seeks to identify and assess factors that contribute to effective independent school governance at the board of trustees level. A review of extant literature reveals two major challenges: (a) definitions and standards of board effectiveness are inconsistent, and (b) there is very little empirical evidence to support existing definitions and notions of effective governance. Study authors have developed a "strategic effectiveness" metric to encompass factors associated with perceptions of board effectiveness and an "institutional performance" metric that includes factors that are critical to the sustainability of independent schools. Survey respondents include 806 heads of school and board chairs. School leaders at six independent schools in the Northeast, Midwest, and the South were interviewed to gather empirical data regarding strategic board governance and institutional performance. This study identifies two areas that impact school leaders' ability to think and act strategically: (a) intentional acculturation of trustees over extended periods of time ("onboarding") and (b) strategic identification and cultivation of potential trustees. Both of these factors impact strategic effectiveness and contribute positively to institutional performance.