Upper crossed syndrome (UCS) refers to the altered muscle activations and movement patterns in scapulae along with some abnormal alignment in the upper quarter, which may contribute to the dysfunction of the cervicothoracic and glenohumeral joints. The present study aimed to investigate the effectiveness of a comprehensive corrective exercise program (CCEP) and subsequent detraining on alignment, muscle activation, and movement pattern in men with the UCS. This randomized controlled trial included 24 men. The intervention group conducted CCEP (8 weeks), followed by four weeks of detraining and the control group maintained normal daily activities. Electromyography of selected muscles, scapular dyskinesis test, head, shoulder, and thoracic spine angle were measured at baseline, post-test, and follow-up. There were significant differences for Group x time interaction and also for within-group from pre-test to post-test and follow-up in all outcomes. Also, significant differences were observed in three outcomes at post-test and follow-up between the CCEP and control group in favor of the CCEP. In Conclusion, the present study demonstrates that the CCEP for individuals with UCS is feasible and effective, improving muscle activation imbalance, movement patterns, and alignment. Importantly, these improvements were maintained after four weeks of detraining, suggesting lasting neuromuscular re-training adaptations.