A 50-year-old man presented with mild unconsciousness after a fall-induced head injury. Initial imaging revealed a left-sided acute subdural hematoma. After transportation to our hospital, his condition deteriorated, leading to the discovery of a new hemorrhage and an anterior falcine artery aneurysm upon further examination. The patient underwent successful decompressive craniectomy and endovascular occlusion. This case, the first reported of a traumatic anterior falcine artery aneurysm, suggests the initial injury caused both the hematoma and aneurysm. The aneurysm's specific location near the crista galli likely contributed to the formation of the traumatic aneurysm, and the compression of the left frontal lobe by the acute subdural hematoma caused the subsequent hemorrhage. This case highlights the importance of considering traumatic aneurysms in atypical postinjury hemorrhages and adds to the understanding of traumatic intracranial aneurysms' mechanisms.