The Life's Simple 7 (LS7) metric consists of 7 modifiable health behaviors and measures that are known health factors for cardiovascular wellness. Relatively little is known about the association of LS7 score with cardiac arrhythmias. In the setting of the Multi-Ethnic Study of Atherosclerosis, we studied the LS7 score (range 0 to 14), assessed at the 2010 to 2102 study visit, in relation to cardiac arrhythmias assessed by Zio Patch ambulatory electrocardiographic monitoring in 2016 to 2018. In participants free of clinically recognized cardiovascular disease and atrial fibrillation, we used logistic and linear regression to examine the association of total LS7 score with atrial fibrillation, supraventricular ectopy, and ventricular ectopy. In 1,329 participants in the analysis, the mean (SD) age was 67 (8) years and 48% were men. A more favorable total LS7 score was associated with fewer premature ventricular contractions (PVCs) per hour (ratio of geometric means for optimal [11 to 14] versus inadequate [0 to 7] score 0.52 [95% confidence interval 0.34 to 0.81]). After adjustment for sociodemographic characteristics, the association was attenuated (0.66 [0.43 to 1.01]). =Among the LS7 components, a more favorable body mass index was associated with less ventricular ectopy. We did not detect associations of total LS7 score with atrial arrhythmias. In conclusion, in this longitudinal study of older participants free of clinically recognized cardiovascular disease, there was little evidence of association of the LS7 cardiovascular health score with subclinical cardiac arrhythmias. However, there was a suggestion that a more favorable LS7 score was associated with fewer PVCs and specifically, that a more favorable body mass index was associated with fewer PVCs.