Background Life's Essential 8 (LE8) is an enhanced metric for cardiovascular health. The interrelations among LE8, biomarkers of aging, and disease risks are unclear. Methods and Results LE8 score was calculated for 5682 Framingham Heart Study participants. We implemented 4 DNA methylation‐based epigenetic age biomarkers, with older epigenetic age hypothesized to represent faster biological aging, and examined whether these biomarkers mediated the associations between the LE8 score and cardiovascular disease (CVD), CVD‐specific mortality, and all‐cause mortality. We found that a 1 SD increase in the LE8 score was associated with a 35% (95% CI, 27–41; P =1.8E‐15) lower risk of incident CVD, a 36% (95% CI, 24–47; P =7E‐7) lower risk of CVD‐specific mortality, and a 29% (95% CI, 22–35; P =7E‐15) lower risk of all‐cause mortality. These associations were partly mediated by epigenetic age biomarkers, particularly the GrimAge and the DunedinPACE scores. The potential mediation effects by epigenetic age biomarkers tended to be more profound in participants with higher genetic risk for older epigenetic age, compared with those with lower genetic risk. For example, in participants with higher GrimAge polygenic scores (greater than median), the mean proportion of mediation was 39%, 39%, and 78% for the association of the LE8 score with incident CVD, CVD‐specific mortality, and all‐cause mortality, respectively. No significant mediation was observed in participants with lower GrimAge polygenic score. Conclusions DNA methylation‐based epigenetic age scores mediate the associations between the LE8 score and incident CVD, CVD‐specific mortality, and all‐cause mortality, particularly in individuals with higher genetic predisposition for older epigenetic age.