This study examined participant demographic and physical function characteristics from EnhanceFitness, an evidence-based physical activity program for older adults. The sample consisted of 19,964 older adults. Participant data included self-reported health and demographic variables, and results for three physical function tests: chair stand, arm curls, and timed up-and-go. Linear regression models compared physical function test results among eight program site types. Participants were, on average, 72 years old, predominantly female, and reported having one chronic condition. Residential site participants' physical function test results were significantly poorer on chair stand and timed up-and-go measures at baseline, and timed up-and-go at a four-month follow-up compared with the reference group (senior centers) after controlling for demographic variables and site clustering. Evidence-based health-promotion programs offered in community settings should assess demographic, health, and physical function characteristics to best serve participants' specific needs, and offer classes tailored to participant function and ability while maintaining program fidelity.