Finger and partial finger amputations are one of the most frequently encountered forms of partial hand loss. Most of these amputees can benefit from prosthetic fingers, which should be both functional and aesthetic, to enhance rehabilitation by permitting a more normal professional and social life. Custom prosthetic fingers perform better than off-the-shelf ones due to better fit, comfort, and match to the patients’ physical characteristics. The conventional fabrication process for custom prosthetic fingers uses multiple impressions and molds combined with silicone injection molding to create the final shape. This process has not seen significant changes for decades and comes with a high cost and long wait time, stopping the prosthesis from benefitting the patient in a cost-effective, timely, and lifelike functional way. This study developed a new manufacturing approach for custom prosthetic fingers based on an additive manufactured custom thin-wall mold. The approach was based on optical 3D scanning of the amputees’ fingers and computer-aided design of custom finger prosthetic geometry and the corresponding thin-wall mold. Preliminary clinical study on an amputee patient shows the feasibility of this new custom molding approach and future work will clinically evaluate the performance of the prosthetic fingers created via the computer-aided design and additive manufacturing approach.