Walking interventions improve health outcomes among older adults. However, few clinical trials evaluate long-term behavior change adherence. The authors explored factors that influence walking adherence in older adults following their participation in a clinical trial. They conducted n = 7 focus groups with n = 23 participants enrolled in the parent study (ClinicalTrials.gov number: NCT03654807). The authors used content analysis to code data according to the social–ecological model. They found that supportive services (exercise classes) in retirement communities have multilevel impacts on adherence to walking activity. Residents from communities offering services continued walking because of increased confidence gained in the parent trial, while residents in communities without services were motivated by their functional improvements. Residents voiced frustration with retirement community physical activity programs that did not address the full spectrum of physical functioning. Findings support the need for retirement communities to account for various motivational factors in tailoring programs to promote increased physical activity for older adults.