Hecht Syndrome is an autosomal dominant distal arthrogryposis caused by mutation in the MYH8 locus characterized by trismus and pseudocamptodactyly. Hecht-associated trismus is thought to result from bilateral hyperplasia of the mandibular coronoid processes. Although several interventions to address trismus have been pursued, no consensus exists regarding optimal management. In this report, the authors present a 7-month-old male with Hecht Syndrome referred for management of trismus. By age 2, interincisal opening had progressively decreased from 12 to 5 mm despite physical therapy. Nutrition was limited to liquids, oral hygiene was compromised, and aspiration risk was present. Computed tomography examination revealed enlarged coronoid processes extending medially and superiorly to the zygomatic arches. To release bony impaction of the coronoid processes against the zygoma and to prevent reossification of the temporalis tendon insertion, resection of the enlarged coronoids and distal temporalis muscles as well as placement of Alloderm spacers were performed via an open craniofacial transzygomatic approach. Jaw motion rehabilitation was used following surgery. Two years postoperatively, the patient had no signs of recurrence and good functional stability of jaw excursion. He was able to chew and swallow solid foods, protrude his tongue, use utensils, and perform regular oral hygiene, none of which were possible before surgery. This case demonstrates that open bilateral coronoidectomy can be a successful and durable management option for trismus in patients with Hecht Syndrome. The open transzygomatic approach is safe, has low morbidity, and provides direct access and adequate exposure for coronoid resection, spacer placement, and prevention of temporalis reinsertion.