Background <p>Prefrail older adults face a higher risk of progressing to frailty, and preventing this progression may reduce mortality. However, evidence on the effectiveness of nurse-led, community-based programs with an integrated approach remains limited. We aimed to develop and evaluate the effectiveness of a nurse-led frailty prevention (NurFP) program in prefrail older adults living in the community. The program was developed based on an ecological framework that addresses frailty risk factors and corresponding intervention strategies across intrapersonal, interpersonal, and community levels, and incorporates a nurse-led multidisciplinary approach.</p> Methods <p>A mixed-methods, quasi-experimental, pragmatic trial was conducted using a pretest-posttest design over a 12-week interval. Participants were forty prefrail older adults residing in Seoul, South Korea. Four administrative units within J district in Seoul were pair-matched based on community characteristics, with two units assigned to the NurFP group and the remaining two to the control group. Participants were recruited from each of NurFP (<i>n</i> = 20) and control (<i>n</i> = 20) groups using convenience sampling. The NurFP group received a 12-week program with main intervention modes of group education and walking sessions; the control group received a single health counselling session. Primary outcome was frailty score; secondary outcomes were intrapersonal, interpersonal, and community-level risk factors for frailty. Outcomes were measured via self-reported questionnaires, of which the community-level factor was assessed to explore perceived supportive environment for frailty prevention using focus group interview following the intervention.</p> Results <p>Compared to the control group, the NurFP group demonstrated a significant reduction in frailty scores (<i>p</i> = .025), with notable improvements in the physical (<i>p</i> = .037) and social (<i>p</i> = .020) domains. The NurFP group exhibited greater improvements in intrapersonal-level factors, including adherence to physical activity (<i>p</i> &lt; .001) and chronic disease self-management (<i>p</i> &lt; .001), as well as in interpersonal-level factors such as perceived social support (<i>p</i> &lt; .001). Focus group interviews revealed heightened awareness of supportive community environments for frailty prevention among the NurFP group and their key stakeholders.</p> Conclusions <p>The NurFP program may improve frailty and its ecological multi-level risk factors and serve as a feasible community-based intervention model for frailty prevention.</p> Trial registration <p>This study has been retrospectively registered with the Clinical Research information Service (CRIS) of South Korea on May 24, 2025 (KCT0010511).</p>