Background/Objectives: Advanced heart failure is associated with reduced functional capacity and impaired quality of live. Left ventricular assist devices (LVADs) are increasingly used as a long-term treatment option in patients with end-stage heart failure. Despite improvements in hemodynamic function after LVAD implantation, many patients continue to experience limitations in daily functioning. The aim of this study was to evaluate the relationship between physical activity and functional status in patients with LVAD support. Methods: The study included 262 adult participants divided into four groups according to LVAD support and declared physical activity. Functional status and quality of life were assessed using the Short Form-36 Health Survey (SF-36) and the Minesota Living with Heart Failure Questionnaire (MLHFQ). Results: Significant differences were observed between the analyzed groups in both SF-36 and MLHFQ scores. Physically active patients with LVAD achieved the most favorable results, indicating better functional status and lower symptom burden, whereas inactive individuals demonstrated poorer outcomes. Significant correlations were found between physical activity and selected aspects of daily functioning, including walking, climbing stairs, household activities, and carrying groceries. Higher levels of physical activity were associated with better quality of life and fewer functional limitations. Conclusions: Physical activity may positively influence functional status and quality of life in patients with LVAD support. The findings suggest that regular physical activity should be considered an important component of rehabilitation and long-term management in patients with advanced heart failure treated with LVAD therapy.