The purpose of this study was to identify principals' instructional leadership actions within a comprehensive teacher evaluation system in successful schools rated as recognized or exemplary by the accountability measures in place. The study followed a multiple case study approach. Participants included six school administrators within the same school district. From these three were principals and three assistant principals, representing all three schools levels--elementary school, middle school, and high school. The main data sources consisted of interviews, observations and journaling. Data were analyzed inductively to discern emerging themes. Findings of the study revealed that principals' instructional leadership actions at all three levels included setting clear expectations, monitoring instruction through walk-through observations, and providing professional development opportunities according teachers' needs. Furthermore, the cross site analysis revealed that principals tend to rely on instructional leadership actions that are pertinent to each grade level's needs. Findings also suggest that principals, indeed, apply the teacher performance appraisal system as a basis to enhance instruction and improve student achievement.