The burden of antimicrobial resistance (AMR) has been increasing worldwide including Thailand. Global Antimicrobial Resistance Surveillance System (GLASS) and antimicrobial stewardship (AMS) are two important pillars of the global action plan on AMR launched by the World Health Organization (WHO) in 2015. Our project aimed to evaluate the impact and feasibility of customised AMS strategies implementation (GLASS antibiogram, Clinical Practice Guideline (CPG) for common infections (bacteremia or sepsis without identified source, urinary tract infections and pneumonia), and antibiotic authorization) under the support of the AMS team at the university hospital. Therefore, we conducted a quasi-experimental (pre- and postintervention) study at three participating hospitals: Sakaeo Crown Prince Hospital, Surin Hospital, and Surat Thani Hospital. Before starting the project, we conducted a national survey to identify the obstacles for AMS implementation at 399 hospitals in Thailand. The major obstacles of AMS program (ASP) implementation identified in this survey were increased workload, lack of AMS knowledge and skills of relevant personnel, and lack of hospital administrator concern. During Jan 2020-Dec 2021, the study enrolled a total of 6,625 patients from three participating hospitals. The summary results of each study are shown below. 1. GLASS antibiogram: Laboratory-based antibiograms from 2019 and GLASS-based antibiograms from 2020 were created and compared. Prevalence of multidrug-resistance in community-acquired infection (CAI)-related bacteria was higher than those in hospital-acquired infection (HAI)-related bacteria, which may have been related to misclassification of colonized bacteria as “true” pathogens and HAIs as CAIs. The results of this study on AMR surveillance using GLASS methodology may not be valid owing to several inadequate data collections and the problem of specimen contamination. Given these considerations, the related personnel should receive additional training on the best practice in specimen collection and the management of AMR surveillance data using the GLASS approach. 2. Clinical practice guideline After the CPG implementation, there were significant reductions in the mean duration of intensive care unit stay, and the mean duration of ventilator use. The CPG-implementation was independently associated with favourable clinical outcomes. These findings confirmed that the locally developed CPG implementation is feasible and effective in improving patient outcomes and reducing antimicrobial consumption. 3. Antibiotic authorization: Implementation of antibiotic authorization could reduce the amount of targeted antimicrobial consumption, the mean length of hospital stay, and increase the favourable clinical response. The study findings confirmed that implementation of antibiotic authorization at provincial hospitals under experienced AMS team’s guidance was feasible and useful. In conclusions, our studies confirmed that the implementation of GLASS antibiogram, CPG, and antibiotic authorization at non-university hospitals under the guidance of an experienced AMS team could reduce inappropriate antimicrobial consumption and improve patients’ clinical outcomes. However, the COVID-19 situation during the postimplementation period may confound the study results. It was possible that the pattern of antimicrobial use and characteristics of hospitalized patients altered by the COVID-19 situation. Therefore, we do believe that the study findings could be a good model for the implementation of customized AMS strategies at other hospitals with limited resources. The related personnel should receive additional training to strengthening the ability to perform a good practice in AMR surveillance and AMS program.