Background: Cardiomyopathy and hypertensive diseases are major contributors to cardiovascular mortality in the United States. Chronic hypertension is associated with adverse myocardial remodeling and may increase the risk of cardiomyopathy. However, national mortality trends involving their coexistence remain poorly characterized. Methods: We analyzed CDC WONDER Multiple Cause of Death data (1999–2025) for adults aged ≥ 25 years with cardiomyopathy (ICD-10: I42) and hypertension (ICD-10: I10–I15) listed anywhere on the same death certificate. Age-adjusted mortality rates (AAMRs) were calculated using the 2000 U.S. standard population, and temporal trends were assessed using Joinpoint regression to estimate APCs and AAPCs. Results: A total of 223,574 deaths were identified. Overall AAMR increased from 2.13 to 4.16 per 100,000 between 1999 and 2025 (AAPC: 2.10%; 95% CI: 1.36–2.64; p < 0.001). Mortality was consistently higher among males than females and was highest in Black individuals (mean AAMR: 8.12) and lowest in Asian/Pacific Islanders (2.34). Mortality increased with advancing age. Regionally, the South had the highest mean AAMR (3.94) and the Northeast the lowest (2.76), whereas the Midwest had the highest AAMR in 2025 (4.83). Non-metropolitan populations experienced greater mortality increases than metropolitan populations (AAPC: 3.53% vs. 1.94%). The District of Columbia had the highest state-level AAMR (7.2), whereas Massachusetts had the lowest (1.4). Home was the largest single setting of death (35.1%). Conclusion: Mortality involving cardiomyopathy and comorbid hypertensive diseases increased from 1999 to 2025, with disparities by sex, race, age, geography, and urbanization. These findings identify populations and regions with disproportionately high mortality and may help inform future research, prevention strategies, and health policy interventions.