Background: According to a report from the WHO, an estimated 1.13 billion people worldwide have hypertension. Medication therapy management (MTM) service is a clinical service based on the theoretical and methodological framework of pharmaceutical care practice, which aims to ensure the best therapeutic outcomes for the patient by identifying, preventing, and resolving drug therapy problems (DTPs). Purpose: The goal of this study was to determine the impact of MTM on hypertension management in Ethiopia. Methods: A pre-post interventional study design was used. Descriptive statistics, linear regression, and logistic regressions were employed to present and analyze data. Results: The final analysis included 279 patients out of 304, with a 7.8% attrition rate. The prevalence of drug therapy problems (DTPs) reduced from 63.4% at baseline to 31.5% during the post-intervention phase. Polypharmacy (AOR = 2.46; 95% CI: 1.27-4.77) and complications (AOR = 0.52; 95% CI: 0.27-0.99) were substantially associated with DTPs at the start of the study. The MTM resulted in a significant reduction in mean systolic blood pressure (SBP) (AOR = 5.31, 95% CI (3.50-7.11), P < .001), as well as a significant increase ( P < .001) in the number of study patients who reached a target BP. At the end of the MTM intervention, non-adherence was linked with DTP (AOR = 2.40; 95% CI: 1.33-4.334) and living outside Addis Ababa (AOR = 1.73; 95% CI: 1.38-1.88). On average, treatment satisfaction was 86.55% (+SD) 10.34. Conclusion: To resolve DTPs and improve clinical outcomes, the MTM service was critical. The majority of patients were found to be compliant with a high treatment satisfaction score.