Importance: Cardiac troponin is associated with incident heart failure and greater left ventricular (LV) mass. Its association with LV systolic and diastolic functions is unclear. Objectives: To define the association of high-sensitivity cardiac troponin T (hs-cTnT) with LV systolic and diastolic functions in the general population, and to evaluate the extent to which that association accounts for the correlation between hs-cTnT concentration and incident heart failure overall, heart failure with preserved LV ejection fraction (LVEF; HFpEF), and heart failure with LVEF less than 50%. Design, Setting, and Participants: This analysis of the Atherosclerosis Risk in Communities (ARIC) Study, an ongoing epidemiologic cohort study in US communities, included participants without cardiovascular disease (n = 4111). Available hs-cTnT measurements for participants who attended ARIC Study visits 2 (1990 to 1992), 4 (1996 to 1998), and 5 (2011 to 2013) were assessed cross-sectionally against echocardiographic measurements taken at visit 5 and against incident health failure after visit 5. Changes in hs-cTnT concentrations from visits 2 and 4 were also examined. Data analyses were performed from August 2017 to July 2018. Main Outcomes and Measures: Cardiac structure and function by echocardiography at visit 5, and incident heart failure during a median 4 1/2 years follow-up after visit 5. Results: Of the 6538 eligible participants, 4111 (62.9%) without cardiovascular disease were included. Among these participants, 2586 (62.9%) were female, and the mean (SD) age was 75 (5) years. Median (interquartile range) hs-cTnT concentration at visit 5 was 9 (7-14) ng/L and was detectable in 3946 participants (96.0%). After adjustment for demographic and clinical covariates, higher hs-cTnT levels were associated with greater LV mass index (adjusted mean [SE] for group 1: 33.8 [0.5] vs group 5: 40.1 [0.4]; P for trend <.001) and with worse diastolic function, including lower tissue Doppler imaging e' (6.00 [0.07] vs 5.54 [0.06]; P for trend <.001), higher E/e' ratio (11.4 [0.2] vs 12.9 [0.1]; P for trend <.001), and greater left atrial volume index (23.4 [0.4] vs 26.4 [0.3]; P for trend <.001), independent of LV mass index; hs-cTnT level was not associated with measures of LV systolic function. Accounting for diastolic function attenuated the association of hs-cTnT concentration with incident HFpEF by 41% and the association with combined heart failure with midrange and reduced ejection fraction combined (LVEF <50) by 17%. Elevated hs-cTnT concentration and diastolic dysfunction were additive risk factors for incident heart failure. For any value of late-life hs-cTnT levels, longer duration of detectable hs-cTnT from midlife to late life was associated with greater LV mass in late life but not with worse LV systolic or diastolic function. Conclusions and Relevance: This study shows that higher hs-cTnT concentrations were associated with worse diastolic function, irrespective of LV mass, but not with systolic function; these findings suggest that high levels of hs-cTnT may serve as an early marker of subclinical alterations in diastolic function that may lead to a predisposition to heart failure.