Facial asymmetry associated with unilateral condylar hyperplasia (UCH) is a rare disease. The aim of this study was to evaluate the clinical conditions of progressive facial asymmetry in young subjects treated with high condylectomy. A retrospective study was performed including nine subjects diagnosed with UCH type 1B and progressive facial asymmetry around 12 years old with an upper canine progressing towards dental occlusion. After an analysis and a decision of treatment, orthodontics began one to two weeks prior to the condylectomy (with a mean vertical reduction of 4.83 ± 0.44 mm). Facial and dental asymmetry, dental occlusion, TMJ status and an open/closing mouth were analyzed before surgery and in the final stage of treatment, almost 3 years after surgery. Statistical analyses were performed using the Shapiro-Wilk test and a Student's t-test considering a p value of <0.05. Comparing T1 (before surgery) and T2 (once orthodontic treatment was finalized), the operated condyle showed a similar height to that observed in stage 1 with a 0.12 mm difference in height ( p = 0.8), whereas the non-operated condyle showed greater height increase with an average of 3.88 mm of vertical growth ( p = 0.0001). This indicated that the non-operated condyle remained steady and that the operative condyle did not register significant growth. In terms of facial asymmetry in the preoperative stage, a chin deviation of 7.55 mm (±2.57 mm) was observed; in the final stage, there was a significant reduction in the chin deviation with an average of 1.55 mm (±1.26 mm) ( p = 0.0001). Given the small number of patients in the sample, we can conclude that high condylectomy (approx. 5 mm), if performed early, especially in the mixed-dentition stage before full canine eruption, is beneficial for the early resolution of asymmetry and thus the avoidance of future orthognathic surgery. However, further follow-up until the end of facial growth is required.