Impaired activities of daily living (ADL) significantly affect the prognosis and quality of life in patients with heart failure (HF). We aimed to identify the key clinical and self-management predictors of ADL 12 months after hospital discharge. This prospective cohort study enrolled 162 hospitalized patients with HF stratified into low-ADL (ADL < 100, n = 66) and high-ADL (ADL = 100, n = 96) groups based on 12 months of follow-up. The baseline characteristics, comorbidities, biomarkers (B-type natriuretic peptide [BNP]), and self-management domains (psychological, drug, dietary, and symptom management) were compared. Logistic regression was used to identify ADL predictors. Subgroup analyses of left ventricular ejection fraction (LVEF) were performed. The low-ADL group had significantly higher rates of valvular heart disease (VHD; 12% vs 3%, P = .025) and diabetes mellitus (29% vs 16%, P = .043), elevated BNP levels (median 474.9 vs 398.0 pg/mL, P = .039), and poorer self-management scores (P < .05). Multivariable analysis confirmed that diabetes (adjusted odds ratio [aOR], 0.33; 95% confidence interval [CI], 0.14-0.80; P = .014) and VHD (aOR, 0.19; 95% CI, 0.04-0.80; P = .024) were independent negative predictors. Symptom management was the strongest positive predictor (crude OR, 12.71; 95% CI, 3.38-47.74; P < .001; aOR, 6.26; 95% CI, 1.44-27.19; P = .014). Stratification by LVEF revealed that diabetes mellitus disproportionately impaired ADL in patients with heart failure with reduced ejection fraction (HFrEF; defined as LVEF < 50%; OR, 0.21; 95% CI, 0.06-0.82). The factors influencing ADL scores changed over the 12-month follow-up period. Diabetes, VHD, and poor symptom management were key predictors of long-term ADL impairment in patients with HF. Targeted interventions addressing symptom management and comorbidity control, particularly in patients with HFrEF, may improve functional outcomes.