Objective: To evaluate the impact of a function-focused multicomponent exercise program on long-term nursing home (LTNH) residents' ability to maintain activities of daily living (ADL), physical performance, cognitive function, quality of life, and frailty., Methods: This multicenter single-group pre-post quasi-experimental study involved 148 participants from 16 LTNHs in Gipuzkoa, Spain. Participants underwent a twice-weekly, 6-month function-focused multicomponent exercise program and were assessed both before and after the intervention., Results: Following the intervention, participants significantly maintained ADL ability, improved physical performance and quality of life, and reduced frailty (all p < 0.05). Cognitive function showed a positive trend. Subgroup analysis showed consistent improvements across demographics and health variables., Conclusions: The exercise program effectively maintained or improved ability to perform ADL, cognitive function, physical performance, and quality of life while reducing frailty in LTNH residents, irrespective of individual characteristics. This highlights the importance of exercise interventions to preserve overall function and wellbeing in this population., Trial Registration: NCT04221724., Competing Interests: Declaration of competing interest None., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)