Introduction Low back pain (LBP) has been reported as the most common reason for presentation to the Medical Centre in the British Military, and the most common re-referral for the same condition. In 2015, the UK Defence Medical Rehabilitation Centre (DMRC) adopted a cognitive functional therapy (CFT) approach to spinal rehabilitation in line with National Institute for Health and Care Excellence and military best practice guidelines. The aim of this study is to evaluate the functional and psychosocial outcomes of all patients with chronic LBP treated with CFT-based multidisciplinary rehabilitation at DMRC, Headley Court. Methods A prospective observational service evaluation of British Military patients (n=238) with LBP who attended 3 weeks of inpatient multidisciplinary CFT-based programme from 2015 to the end of 2017 at DMRC was analysed. Functional outcomes include: multistage locomotion test (MSLT) and sit and reach test. Psychosocial outcomes include: Tampa Scale of Kinesiophobia, Oswestry Disability Index, Brief Pain Inventory (BPI), General Anxiety Disorder-7 and Patient Health Questionnaire-9. Results There were significant improvements in endurance (MSLT), range of motion, kinesiophobia, pain-related lifestyle interference (BPI-Lifestyle), anxiety and depression (p≤0.001). However, no improvements in pain intensity (BPI-Intensity) were demonstrated (p>0.05). Conclusion After 3 weeks of CFT-based multidisciplinary rehabilitation, function and psychosocial health improved with symptoms of pain being less obtrusive to activities of daily activity. There were however no patient-reported reductions in pain intensity. The improvements demonstrated are indicative of outcomes that facilitate greater integration back to work or into society.