Renal trauma is the most frequent type of genitourinary injury, while unilateral renal agenesis is an uncommon congenital anomaly. When trauma involves a solitary kidney, it raises significant concern due to the risk of compromised overall renal function. We report the case of a 25-year-old male patient presenting with blunt trauma to the right flank following a horse kick. Imaging revealed a Grade III renal injury in a solitary kidney due to contralateral agenesis. The patient was managed conservatively with close monitoring and supportive care, resulting in a favorable clinical and radiological outcome. This case highlights the effectiveness of non-operative management in hemodynamically stable patients, even in the context of a solitary kidney, with careful surveillance to prevent complications.