The management of the middle mesial canal (MMC) in mandibular first molars presents considerable challenges during endodontic treatment due to its complex anatomy. Challenges may arise throughout various stages of treatment, including canal location, instrumentation, and obturation. The inability to identify and shape this canal can lead to endodontic failure and post-treatment apical periodontitis. Therefore, understanding this aberrant root canal anatomy and its clinical implications during the various stages of endodontic treatment is essential for successful management, including the selection of the optimal coronal restoration to enhance the efficacy of the obturation’s coronal seal and to ensure the restoration’s maximal longevity. This case report describes the diagnosis and successful endodontic and restorative management of an MMC in a mandibular first molar.