Effective rehabilitation strategies are lacking for medically complex older veterans leading to insufficient care and perpetuating accelerated health decline complicated by falls, hospitalizations, and premature death. Many older veterans with medical complexity experience one or more of the following: multimorbidity, reduced access to healthcare, social vulnerabilities such as loneliness or isolation, impaired physical function, and physical inactivity. These factors highlight the variable complexity and clinical presentation of older veterans, helping to explain why traditional rehabilitation strategies and programs are ineffective and insufficient. To address this critical gap in healthcare services, we developed and evaluated a MultiComponent TeleRehabilitation (MCTR) program using mixed methods intervention development. The MCTR program was designed to address (1) impaired physical function through high-intensity rehabilitation, (2) personal factors contributing to physical activity behavior such as motivation and self-efficacy through a biobehavioral intervention, (3) social isolation and loneliness through social support provided via group telerehabilitation, and (4) reduced access to healthcare through technologies. Results from the first iteration of the MCTR program supported its feasibility for veterans 50 years and older with at least 3 medical conditions while providing key insights for how to improve recruitment and enrollment procedures, adapt the intervention, and modify the integration of technologies. These insights led to key changes that were implemented and evaluated during a randomized feasibility study. Primary results from this latter study supported the feasibility and safety of the updated MCTR program. Secondary results also demonstrated a signal for improvement of patient level outcomes including physical function and helped to identify salient differences between participants who engaged with the technology and those who did not engage with the technology. These latter findings are important because there appears to be a trend of better outcomes among those who engaged with the technology to support behavior change. Therefore, by understanding reasons why people did not engage in the technology, we can adapt the MCTR program to address and mitigate these barriers and ultimately improve patient outcomes. Comprehensively, these results are significant because they provide evidence for effective multicomponent programs that have the potential to broaden healthcare access for adults with medical complexity.