This qualitative study was conducted for the purpose of determining whether a district mathematics curriculum leader's social network advanced the implementation of the high school mathematics Common Core State Standards (CCSS) (CCSSI, 2012c). The qualitative data was collected through an interview, a hand-drawn network map, observations, and document reviews. The network map underwent an egocentric analysis. The results revealed that the district mathematics curriculum leader's network advanced the high school mathematics Common Core State Standards (CCSSI, 2012c) implementation reform effort by working interdependently, not in isolation with other mathematics teachers; fostering independence and innovation in professional learning; and having inclusive influences in the network. [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://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]