BACKGROUND: Guidelines recommend antihypertensive medication for adults with both stage 1 hypertension (systolic blood pressure, 130–139 mm Hg or diastolic blood pressure, 80–89 mm Hg) and 10-year atherosclerotic cardiovascular disease (ASCVD) risk ≥10%. Cardiac biomarkers could facilitate a more targeted approach to the treatment of stage 1 hypertension. METHODS: We studied 1999 to 2004 National Health and Nutrition Examination Survey participants aged ≥20 years with untreated stage 1 hypertension without heart failure or ASCVD. hs-cTnI (high-sensitivity cardiac troponin I) and hs-cTnT (high-sensitivity cardiac troponin T) and NT-proBNP (N-terminal pro-B-type natriuretic peptide) were measured in stored serum. We used the Pooled Cohort Equations to predict 10-year ASCVD risk. All participants had linked mortality follow-up through December 31, 2019. RESULTS: Overall, 17.5% of US adults (32.2 million) had untreated stage 1 hypertension. Among these 32.2 million persons, 15.7% had ASCVD risk ≥10%, 5.6% had elevated hs-cTnI, 4.7% had elevated hs-cTnT, and 9.5% had elevated NT-proBNP. Among adults aged 65 to 79 years with untreated stage 1 hypertension, 80.5% had ASCVD risk ≥10%, 13.0% had elevated hs-cTnI, 15.2% had elevated hs-cTnT, and 29.4% had elevated NT-proBNP. Less than half of the adults aged ≥80 years with untreated stage 1 hypertension had elevated biomarkers. The cardiovascular disease mortality rates among all adults with untreated stage 1 hypertension and with either ASCVD risk ≥10%, elevated hs-cTnI, elevated hs-cTnT, or elevated NT-proBNP were 7.51, 7.74, 8.75, and 5.87 per 1000 person-years, respectively. CONCLUSIONS: Cardiac biomarkers may be more selective for informing risk-based treatment decisions in stage 1 hypertension, particularly among adults aged ≥65 years.