Military personnel are typically healthier at enlistment than the general population, the “healthy soldier effect.” However, this advantage does not guarantee protection against accelerated biological aging over the life course. Military service exposes individuals to chronic stress, combat trauma, and environmental hazards, even as service members benefit from resources linked to slower biological aging, such as healthcare access, educational benefits, and social support. Whether these competing forces produce net accelerated or decelerated biological aging remains unanswered as previous research has only examined biological aging among veteran populations and has yet to compare veterans and non-veterans directly on a nationally representative level. Using data from the Health and Retirement Study (N=3,519), we examined veteran status and three epigenetic clocks, DNA methylation-based biomarkers of biological aging, each trained on specific biological measures of health: PCGrimAge (mortality-predictive plasma proteins), PCPhenoAge (clinical morbidity biomarkers), and Pace of Aging/mPoA45 (rate of decline across 18 organ systems). Because epigenetic clocks increase with chronological age, we computed acceleration scores as residuals from OLS regressions of each clock on chronological age to isolate non-age-dependent biological aging, then regressed each measure on veteran status, adjusting for sex, race/ethnicity, and education. Veterans showed significantly accelerated biological aging on two of three clocks: PCPhenoAge acceleration (β=0.73, SE=0.33, p=.027) and mPoA45 (β=0.02, SE=0.01, p=.032), but not PCGrimAge (β=0.28, SE=0.18, p=.133). Findings suggest the cumulative biological costs of military service produce net epigenetic age acceleration, with variation across clocks reflecting distinct aging dimensions. Results carry implications for future research aiming to better pinpoint the exact epigenetic impacts of military service on biological aging.