Background: This prospective study was designed to investigate whether myocardial triglyceride (TG) content from proton magnetic resonance spectroscopy (MRS) and left ventricular (LV) function parameters from cardiovascular magnetic resonance imaging (CMR) can serve as imaging biomarkers in predicting future major cardiovascular adverse events (MACE) and readmission in patients who had been hospitalized for acute heart failure (HF). Methods: Patients who were discharged after hospitalization for acute HF were prospectively enrolled. On a 3.0 T MR scanner, myocardial TG contents were measured using MRS, and LV parameters (function and mass) were evaluated using cine. The occurrence of MACE and the HF-related readmission served as the endpoints. Independent predictors were identified using univariate and multivariable Cox proportional hazard regression analyses. Results: A total of 133 patients (mean age, 52.4 years) were enrolled. The mean duration of follow-up in surviving patients was 775 days. Baseline LV functional parameters—including ejection fraction, LV end-diastolic volume, LV end-diastolic volume index (LVEDVI), and LV end-systolic volume (p < 0.0001 for all), and myocardial mass (p = 0.010)—were significantly associated with MACE. Multivariable analysis revealed that LVEDVI was the independent predictor for MACE, while myocardial mass was the independent predictor for 3- and 12-month readmission. Myocardial TG content (lipid resonances δ 1.6 ppm) was significantly associated with readmission in patients with ischemic heart disease. Conclusions: LVEDVI and myocardial mass are potential imaging biomarkers that independently predict MACE and readmission, respectively, in patients discharged after hospitalization for acute HF. Myocardial TG predicts readmission in patients with a history of ischemic heart disease.