Background: In response to the 2014 Executive Order on Combating Antibiotic-Resistant Bacteria, the Centers for Disease Control and Prevention (CDC) released “Core Elements of Hospital Antibiotic Stewardship Programs” in 2014 (updated in 2019). Outpatient guidelines were released in 2016. In 2017, the Department of Defense (DoD) required hospitals to establish antimicrobial stewardship (AS) programs (ASPs) that included CDC Core Elements (CEs). DoD ASPs are often evaluated at the hospital level but had previously not been assessed system-wide. This study analyzed DoD ASPs as an enterprise to inform future quality improvement. Methods: Data from an online survey and CDC’s National Healthcare Safety Network (NHSN) hospital annual survey, which includes self-reported responses about facility characteristics and hospital programs (including ASPs), were analyzed in Stata/IC 16.1. A framework analysis was conducted to determine how ASPs were structured, using CDC CEs as a guide. DoD adherence for each individual and total CEs/Priority CEs were compared to national data for 2017-2021 and averaged over the same time frame. Adherence was measured using the dichotomous CDC methodology: a positive response to >1 question within a CE was categorized as that CE being met as well as using a semi-quantitative scoring approach. Associations between CE scores and ASP-related outcomes (antibiotic use and pathogen incidence) were analyzed and re-run to adjust for categorical bed size. Outpatient CE adherence was surveyed and calculated using both dichotomous and scoring methodology. Results: Hospitals and outpatient clinics: ASP leaders were assigned more often than volunteered and most spent 1-25% of their time on AS activities. Most ASPs consisted of ≤25% pharmacists. ASP leaders were largely available on a daily basis (85.0% hospital; 72.8% outpatient). Dichotomous CE adherence was high (≥95.7% hospitals in 2021; ≥84.1% outpatient). Hospitals: Pharmacist leaders spent more time on ASP activities than physicians. Adherence in 2021 lagged national percents in the structural CEs of Leadership (-1.0%), Accountability (-2.5%), and Pharmacy Expertise (-0.9%). Adjusted models indicated that procedural CEs, particularly Priority Reporting, were associated with better ASP-related outcomes. Outpatient clinics: AS efforts were present at 96.3% of ambulatory and 51.7% of dental clinics. Most AS leaders did not have specific training (78.1%). Dental clinics had less pharmacist support (all ambulatory clinics had pharmacist support, 2 of 6 responding dental clinics had no pharmacists). Scoring revealed deficiencies for all CEs. Conclusions: Hospitals and outpatient clinics: Refining CE adherence measures and using quantitative methods provides greater detail to target quality improvement initiatives. ASP-related outcomes should be assessed; patient outcomes should be an important indicator of ASP performance. Hospitals: CEs where DoD hospitals lagged national adherence present opportunities for improvement. Results provide evidence to prioritize procedural CE implementation in hospitals. Outpatient clinics: AS efforts are less robust compared to hospitals. Dental clinics may need additional pharmacist support. Setting-specific resources could facilitate uptake of CEs and results point to initial focus areas to address within the CE subcomponents. An expanded DoD AS leader network would aid communication/dissemination of evidence-based practices. Future research is needed to standardize and regularly conduct AS evaluations in outpatient settings.