Multicomponent physical exercise is effective in curbing the effect of hospitalization in older adults. However, it is not well established which characteristics of the exercise interventions would optimize intervention sustainability and efficacy. This study compared the effects of two group-based multicomponent exercise interventions of different lengths in older adults after hospitalization. Fifty-five participants were randomly assigned to a short-term group-based branch (SGB, n = 27) or to a long-term group-based branch (LGB, n = 28). The SGB participated in a six-week multicomponent group-based exercise-training program followed by 18 weeks of home-based exercise. The LGB completed 12 weeks of each phase. Physical function, physical activity, quality of life, anthropometrics, and nutritional status were assessed at baseline, after 12 weeks, and after 24 weeks of intervention. Both groups improved physical function and nutritional status and increased physical activity after 12 weeks of intervention (paired student’s t-test, p < 0.01), and maintained the positive effects during the following 12 weeks. No group-by-time interaction was observed in any of the studied variables using mixed-model ANOVA. Based on these findings, we determined that 6 weeks of a group-based exercise intervention caused similar functional and nutritional benefits to a longer group-based intervention of 12 weeks when both are continued at home until 24 weeks.