<b><i>Background:</i></b> Older adults often have a greater need for health information and health care services because access to these helps them manage their health and the chronic conditions of aging. Therefore, low health literacy bears a special significance for the population of older adults. <b><i>Objectives:</i></b> The aim of this study was to examine the effects of an active learning program on health literacy, lifestyle behaviors, physical function, and mental health among community-dwelling older adults with low health literacy. <b><i>Methods:</i></b> This single-blind, randomized controlled trial involved 60 participants aged ≥65 years with a low health literacy who were randomly assigned to an intervention (<i>n</i> = 30) or control (<i>n</i> = 30) group. Across 24 weeks, the intervention group attended weekly 90-min active learning program sessions, which involved exploratory learning, group work, and the self-planning of behavior changes that promote a healthy lifestyle. The control group attended a 90-min class, which was taught in accordance with the didactic teaching method. For both groups, the programs focused on the role of exercise, diet/nutrition, and cognitive activity for promoting health among older adults. The outcome measures were administered at baseline and week 24. Comprehensive health literacy (i.e., primary outcome) was assessed using the Health Literacy Scale-14. Lifestyle factors (i.e., physical activity, dietary variety, life-space mobility, and social network size), physical function, and depressive symptoms were measured. We used a linear mixed model to estimate the intervention effects in accordance with the intention-to-treat approach. <b><i>Results:</i></b> When compared to the control group, the intervention group demonstrated a significant improvement in communicative health literacy, step count, engagement in moderate-to-vigorous physical activity, dietary variety, life-space mobility, social network size, grip strength, gait speed, and depressive symptoms. <b><i>Conclusions:</i></b> The active learning program can promote a healthy lifestyle and prevent functional decline among older adults who lack the confidence to engage in health communication.