Pneumonia-related mortality is expected to increase in aging societies. This prospective cohort study examined whether daily walking (1 hour/day) could reduce pneumonia-related mortality among older people who lacked other exercise habits. We analysed data from Japanese Specific Health Checkup across 82 municipalities in 7 prefectures among participants aged ≥65 years who participated in daily walking but did not regularly engage in other forms of exercise (n = 132,448). Information on walking habits and health-related indicators was assessed at a baseline survey conducted between 2008 and 2014. Pneumonia-related and all-cause mortality were followed for a median of 3.4 years. We performed a competing risk model with propensity score matching to evaluate the association between daily walking habits and pneumonia-related mortality. Our propensity-matched analysis revealed a significant association between daily walking and pneumonia-related mortality among older people who lacked other exercise habits, such that the sub-hazard ratio and 95% confidence intervals were 0.58 (0.39, 0.86). This study extends the findings of previous research on the effects of exercise on pneumonia by demonstrating that daily walking alone is sufficient to reduce pneumonia-related mortality among older people who do not regularly engage in other exercise habits.