Background and Purpose: Healthy aging allows older adults to remain active in their communities; however, sedentary behaviors can lead to physical deconditioning and decreased physical function. Structured exercise programs are recommended to facilitate activity engagement and prevent muscle atrophy due to aging to facilitate older adults' abilities to complete activities of daily living. In particular, high-intensity functional training (HIFT) is a multicomponent group exercise program that has previously been shown to increase physical function for middle-age cancer survivors. This study examined the preliminary feasibility and effectiveness of HIFT for improving physical function and participation in physical activity for community-dwelling older adults. Methods: The 8-week pilot study included two 60-minute HIFT sessions per week. Participants (n = 8) were 75% female with a mean age of 71 (6) years. Study initiation, adherence, and acceptability were assessed to determine feasibility. Effectiveness was assessed via 5 physical function measures conducted during sessions 1 and 16 and included the Timed Up and Go, lift and carry test, chair stand test, a repeated stair climb test, and the 6-minute walk test. Participants also self-reported confidence and difficulty for activities of daily living via the Outpatient Physical Therapy Improvement in Movement Assessment Log and physical activity participation via the Community Health Activities Model Program for Seniors questionnaire. Results and Discussion: The study recruitment rate was 88.9% and 87.5% of participants adhered. Intervention acceptability was promising, as 4 participants reported liking multiple aspects of the intervention (eg, coaching/supervision and similar age peers). Intervention effectiveness was promising with significant improvement in 1 of 5 physical function measures, although clinical effects were most likely trivial. Participants reported increased participation in both leisure and structured physical activities. Conclusions: HIFT appeared feasible and showed promise for counteracting the loss of physical function and sedentary behaviors associated with aging. Results should be confirmed in a longer, fully powered study.