Degenerative cervical myelopathy (DCM) is a prevalent cause of spinal cord dysfunction in adults, with surgical intervention being the standard method for preventing neurological decline and enhancing functional outcomes. While smoking is known to impair healing and diminish outcomes in spinal surgery, its specific impact on postoperative recovery in DCM remains uncertain. Few studies have differentiated smoking status from lifetime exposure or assessed detailed neuropathic sensory profiles of smokers. This prospective multicenter cohort study aimed to examine the influence of smoking status and cumulative smoking exposure on postoperative neurological and functional outcomes in patients with DCM. A total of 935 patients with DCM were categorized as non-smokers, past-smokers, or current-smokers. Demographics, operative variables, and outcomes (Japanese Orthopaedic Association (JOA) score, visual analog scale (VAS) pain scores, JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), Short Form-36 physical (PCS) and mental (MCS) component scores, and Neuropathic Pain Symptom Inventory (NPSI)) were compared across groups over a 2-year follow-up. For current-smokers, cumulative exposure was quantified using the Brinkman index and correlated with postoperative outcomes. Current-smokers exhibited significantly lower JOA recovery rates and poorer postoperative JOACMEQ upper- and lower-extremity function compared to non-smokers and past-smokers (p < 0.05). No significant intergroup differences were observed in the JOA score, SF-36 PCS/MCS, VAS, or NPSI. Among current-smokers, the Brinkman index did not correlate with the JOA, JOACMEQ, or SF-36 scores but was significantly associated with reduced improvement in the NPSI-burning (r = 0.678, p = 0.022) and pressing (r = 0.602, p = 0.048) domains. Active smoking was associated with less favorable functional recovery following DCM surgery, whereas cumulative smoking exposure showed no clear relationship with neurological or functional improvements. However, greater cumulative exposure appeared to be associated with persistent neuropathic sensory symptoms. These results suggest that smoking status and cumulative exposure may influence different aspects of postoperative recovery, supporting smoking cessation as part of preoperative patient management.