Two hundred fifty adults recovering from complex lumbar surgery were enrolled and randomized to a behavioral intervention group or an attention control group. The intervention consisted of a structured behavioral program grounded in social cognitive theory, including a walking contract, pedometer use, education on activity benefits, and frequent reinforcing telephone contacts over twelve months. Controls received physical activity information and fewer scheduled contacts. The primary outcome was the within-patient change in weekly energy expenditure from walking, measured using the Paffenbarger Physical Activity and Exercise Index, from enrollment to four months. Secondary outcomes included changes in total physical activity at four and twelve months. Overall, the results of the study revealed that both groups increased physical activity, but patients receiving the behavioral intervention demonstrated significantly greater increases in walking-related energy expenditure at four months, with sustained benefits at twelve months. These findings suggest that embedding behavioral counseling into postoperative spine care effectively promotes long-term lifestyle physical activity.