The purpose of this qualitative case study was to explore how long term, focused, and embedded professional development influenced teachers' self-efficacy and preparedness to implement the Common Core State Standards in a large urban school district in northern Nevada. The sample was 17 7th-12th grade social studies teachers that participated in a three-year cohort Northern Nevada Teaching American History (NNTAH) grant between 2010-2013. The primary research questions explored were: How do social studies teachers perceive long-term, focused, and embedded professional development and their (a) self-efficacy and (b) preparedness to implement the Common Core State Standards? An additional research question included: How do educational administrators perceive long-term, focused, and embedded professional development, teacher self-efficacy, and preparedness to implement Common Core State Standards? Self-efficacy theory was the conceptual model for the study. The data sources included secondary and primary interviews of teachers along with interviews of administrators who conducted observations of the teachers. Results of this study identified themes of how teachers and administrators perceptions of the professional development influenced the participants. The themes for teachers were collaboration, relationships, and the constructivist model of learning. The themes for administrators were teacher leadership, willingness, and shifts in practice. Administrators and teachers may find value in the findings of this study as they relate to how long-term professional development influences teachers' self-efficacy and preparedness to implement Common Core. [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.]