The purpose of this mixed-method case study was to uncover the common experiences of 69 first and second year mathematics coaches, bound by their participation in the Mathematics Coaching Program (MCP). Evidence supporting MCP implementation and the evolution of instructional practices were also investigated and reported. Interview, document, and observation data were collected and analyzed for common themes. These themes included (a) establishing identity, (b) planning for coaching, (c) the coaching process, (d) instructional approaches consistent with the MCP, (e) greatest coaching accomplishments, (f) greatest challenges, and (g) professional development support. These findings provide a voice to MCP coaches, add to current research on the impact of coaching, and highlight the need for supportive structures to promote success. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]