This dissertation empirically analyzes the practices and processes by which US bureaucratic agents develop grand strategies, policies, strategies, and plans since the end of the Cold War. Most scholarship, especially regarding grand strategy and strategy, is normative or didactic. If it is empirical, then it is historical and/or focused on principals. Therefore, scholarship overlooks most of the people who practice and formulate these schemata today and in recent history. This dissertation addresses these gaps by examining the experience of working- and senior-level practitioners to understand their practices and processes. This dissertation seeks to answer the following research questions: 1) what are the processes by which these schemata are developed; 2) how do practitioners impact the development process; and 3) how do practitioners and development processes impact the end product (i.e., the schema)? This research employs an interpretivist-constructivist methodology and utilizes social constructivist and practice theories. Original data were collected through semi-structured interviews with current and former practitioners during fieldwork and via telecommunications. During the interviews, process tracing provided a systematic approach to assist participants in conveying their experiences. Process tracing, along with reflexive thematic analysis were used to interpret the transcripts and interview notes. My findings suggest that three of the earliest decisions made by agents developing national security, military, and foreign policy schemata were: 1) how large the size of effort will be, 2) to whom agents grant entrée into the development space and at which levels, and 3) why agents decide to grant entrée to agents. These latter two decisions are made again throughout the development process. Agents (and principals) socially construct a multilayered space via the constellation of relationships, interactions, powers, and roles. These findings hold true across the interagency, for various schemata, and throughout the development process of the 2018 National Defense Strategy of the United States of America. The findings entail implications for related literatures across several disciplines, civilian and professional military education, and the practices and processes of practitioners and policymakers.