Neurologic deficit after lumbar spine surgery is a rare and serious complication that must be promptly diagnosed and treated to avoid long-term neurologic disability. Anterior lumbar interbody fusion (ALIF) is an effective technique for the treatment of recurrent disc herniation and lumbar disc degeneration. This case report describes a 20-year-old female with L5-S1 recurrent disc herniation and lumbar degeneration. She underwent an L5-S1 ALIF complicated by post-operative lower left extremity paralysis. Revision surgery with downsizing of the ALIF cage was performed with normal neuromonitoring throughout the procedure. The patient displayed persistent post-operative neurologic deficits despite no evidence of central or foraminal compression. Patient was later diagnosed with conversion disorder by neurology during her hospitalization. This case report presents the initial diagnosis of conversion disorder after a routine ALIF procedure, which led to surgical re-exploration and prolonged inpatient hospital stay. Psychiatric diagnoses must be considered when neurologic deficits are present with no apparent organic cause.