Background: Regular exercise improves the functional ability and quality of life of patients with heart failure (HF). However, studies on the results of intensity of exercise in the older population are scarce, especially in the Asian population. Method and Results: A total of 8982 older people (age \ge65 years) with HF were selected from the Korean National Health Insurance Service-Senior database (2005–2012). Participants were stratified according to the levels of physical activity per week as follows: (1) inactive group; (2) insufficiently active group: 1–499 metabolic equivalent task minutes (MET-min)/week; (3) active group: 500–999 MET-min/week; and (4) highly active group: \ge1000 MET-min/week. During a median follow-up period of 3.2 years, the incidence and risk of mortality were reduced in the insufficiently active (6.7 vs. 4.2 per 100 person-years, adjusted hazard ratio [HR], 0.82; 95% confidence interval [CI], 0.71–0.94; p 0.001), active (3.8 per 100 person-years; HR, 0.81; 95% CI, 0.70–0.95; p = 0.010), and highly active (2.4 per 100 person-years; HR, 0.52; 95% CI, 0.41–0.67; p 0.001) groups compared to inactive patients. Conclusions: In older Asians with HF, increased physical activity reduced the risk of all-cause mortality. The mortality-reducing benefit started at a lower physical activity compared to the World Health Organization guideline (500–999 MET-min/week), and the risk decreased with more physical activity.