Background: In the surgery-first approach (SFA) the orthognathic surgery is performed without the need for presurgical orthodontic treatment. Aim: This study was aimed at assessing the treatment durations and occlusal outcomes for a consecutive cohort of patients, with a range of dentofacial deformities, who have completed orthognathic treatment using the SFA. Methodology: The duration of orthognathic treatment was measured. The overall change in occlusion, and the quality of the final occlusion, were evaluated using the patients’ study casts. A single independent, calibrated, operator carried out the occlusal scores, using the validated Peer Assessment Rating (PAR) index. This was repeated to test intra-operator reliability. Results: A total of 51 patients completed surgery-first treatment during the study period. The mean age at surgery was 23.3 years. The pre-treatment skeletal jaw relationship was Class III in 39 cases, and Class II in 12 cases. The mean overall treatment duration was 11.7 months (SD = 5.7). The intra-examiner reliability of assessing the occlusion was high. The PAR scores confirmed a significant improvement in the quality of occlusion at the completion of treatment, which compares favourably with previous studies on the conventional orthodontics-first approach. Conclusion: The SFA can be effective at correcting both Class 2 and Class 3 malocclusion types with reduced treatment times.