Background Many people may underappreciate the role of lifestyle in avoiding heart failure. We estimated whether greater adherence in middle age to American Heart Association's Life's Simple 7 guidelines - on smoking, body mass, physical activity, diet, cholesterol, blood pressure, and glucose - is associated with lower lifetime risk of heart failure and greater preservation of cardiac structure and function in old age. Methods We studied the population-based Atherosclerosis Risk in Communities Study cohort of 13,462 adults ages 45-64 years in 1987-1989. From the 1987-1989 risk factor measurements, we created a Life's Simple 7 score (range 0-14, giving 2 points for ideal, 1 point for intermediate, and 0 points for poor components). We identified 2218 incident heart failure events using surveillance of hospital discharge and death codes through 2011. In addition, in 4855 participants free of clinical cardiovascular disease in 2011-2013, we performed echocardiography from which we quantified left ventricular hypertrophy and diastolic dysfunction. Results One in four participants (25.5%) developed heart failure through age 85 years. Yet, this lifetime heart failure risk was 14.4% for those with a middle-age Life's Simple 7 score of 10-14 (optimal), 26.8% for a score of 5-9 (average), and 48.6% for a score of 0-4 (inadequate). Among those with no clinical cardiovascular event, the prevalence of left ventricular hypertrophy in late life was approximately 40% as common, and diastolic dysfunction was approximately 60% as common, among those with an optimal middle-age Life's Simple 7 score, compared with an inadequate score. Conclusions Greater achievement of American Heart Association's Life's Simple 7 in middle age is associated with a lower lifetime occurrence of heart failure and greater preservation of cardiac structure and function.