Background: Check ligament suspension has been expected to become an alternative to the frontalis technique. However, it has not been widely used because of anatomic controversies, concerns regarding its reliability, and the risk of conjunctival prolapse. This article details the authors’ experience with the use of check ligament suspension for the treatment of severe congenital ptosis and evaluates the functional and cosmetic results. Methods: This single-institution retrospective study included patients who underwent check ligament suspension for severe congenital blepharoptosis from July of 2021 to June of 2023. Preoperative data collected included age, sex, margin reflex distance 1 (MRD1), levator function, and lagophthalmos. Postoperative evaluation including correction result, eyelid closure function, and cosmetic result was performed at the last follow-up. Results: A total of 124 patients (170 eyes) were included in this study. There was a significant improvement between the preoperative and postoperative MRD1, and 159 eyes (93.6%) showed successful correction. Mean postoperative residual lagophthalmos was 0.58 ± 0.57 mm, and 162 eyes (95.3%) showed excellent or good eyelid closure function. The average cosmetic result score was 8.45 ± 1.11; 107 patients (86.3%) had an excellent or good cosmetic result. Conclusions: Check ligament suspension, using the understanding of the extraocular check ligament system to perform the procedure in an effective and anatomically logical manner, has been proven to achieve sufficient corrective results for severe congenital ptosis, with good cosmetic results and minimal complications such as undercorrection, residual lagophthalmos, or conjunctival prolapse. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.