DescriptionWhile many preschool programs are including coaching as a mechanism for professional development, there is little information about how coaches define their roles and responsibilities, how they are prepared to do their jobs, and how to best support successful coaching in early childhood settings. The purpose of this mixed methods comparative case study was to more closely examine the work of early childhood coaches in action. The three research questions guiding the study were: (1) how do instructional coaches define their roles, (2) how do coaches approach their work with teachers, and (3) what factors mediate the work of coaches? Data was gathered from a statewide survey of 64 coaches from throughout the state of NJ, ranging in age and educational background. Two master teachers from 2 different districts were then observed once a month for a period of 5 months. The case study teachers also participated in three structured interviews and kept coaching logs about their activities. The data from the survey, observations, interviews, and coaching logs were initially transcribed and coded separately. Then, further analysis was conducted to identify themes emerging across all data. Findings from this study suggest organizational factors such as district size, curriculum utilized and competing responsibilities influence the coaches’ work. The case study data indicates that the administration’s interpretation of the master teacher role has an influence on how coaches approach their work. In addition to these organizational aspects, individual factors such as age, education and experience were also found to mediate the role of the master teacher.