A comprehensive analysis of clinical information in patients with chronic low back pain (CLBP) was performed to clarify the clinical characteristics of geriatric LBP from the perspective of body composition, spinal alignment, and blood findings related to senescence. We enrolled 203 patients with an average age of 79.0 years (77 men and 126 women), with non-specific CLBP as a single-center prospective cohort study, the patients were compared with age- and sex-matched controls without CLBP using a propensity score-matching. We performed laboratory analysis, radiographic evaluations for global spinal parameter and lumbar degeneration, and body composition analysis using whole-body dual-energy X-ray absorptiometry. We observed a higher red blood cell distribution width (RDW) (p < 0.001), which is an index of aging, as well as a lower vitamin D level (p = 0.002), skeletal muscle mass index (p = 0.045) and a higher fat mass (p = 0.007) in patients with CLBP. Moreover, patients with geriatric CLBP had significantly lower lumbar lordosis (p = 0.024), and higher sagittal vertical axis (p = 0.006) was correlated with lower extremity and trunk muscle mass (p < 0.001), independent of lumbar degeneration. Geriatric patients with CLBP have sarcopenic fat accumulation and spinal sagittal malalignment with senescent status, such as elevated RDW and hypovitaminosis D.