This study investigates the impact of baseline frailty on mortality and post-ICU disability in long-stay ICU patients (7 days or more) at 6 months after critical illness. Using the Clinical Frailty Scale (CFS), patients were categorized into frail (CFS ≥5), pre-frail (CFS 3–4), and non-frail (CFS 1–2). The study included 531 patients, with 33.6% being frail, 37.6% pre-frail, and 28.8% non-frail. Frail patients were older, had more comorbidities, and greater disease severity at ICU admission. At 6 months, frail patients had higher mortality rates (34.3%) compared to pre-frail (21%) and non-frail (13.1%) patients (p < 0.01). Frail patients also had poorer physical health-related quality of life (QoL) but not mental health-related QoL compared to non-frail patients. The CFS is a reliable tool for assessing frailty and can help inform patients and families about the complexities of survivorship during prolonged ICU stays.This study investigates the impact of baseline frailty on mortality and post-ICU disability in long-stay ICU patients (7 days or more) at 6 months after critical illness. Using the Clinical Frailty Scale (CFS), patients were categorized into frail (CFS ≥5), pre-frail (CFS 3–4), and non-frail (CFS 1–2). The study included 531 patients, with 33.6% being frail, 37.6% pre-frail, and 28.8% non-frail. Frail patients were older, had more comorbidities, and greater disease severity at ICU admission. At 6 months, frail patients had higher mortality rates (34.3%) compared to pre-frail (21%) and non-frail (13.1%) patients (p < 0.01). Frail patients also had poorer physical health-related quality of life (QoL) but not mental health-related QoL compared to non-frail patients. The CFS is a reliable tool for assessing frailty and can help inform patients and families about the complexities of survivorship during prolonged ICU stays.