Renal cell carcinoma (RCC), the most common form of kidney cancer, is often diagnosed incidentally through routine imaging or unexplained laboratory abnormalities. We report the case of a 62-year-old male with a medical history of type 2 diabetes mellitus, hypertension, dyslipidemia, and previously treated hepatitis C, who presented with an asymptomatic, mildly elevated alanine aminotransferase (ALT) level discovered during routine follow-up. Despite normal values for other liver enzymes, an abdominal ultrasound performed to investigate the abnormal ALT revealed a well-defined lesion in the left kidney. Further imaging with contrast-enhanced CT confirmed the presence of a renal mass, and histopathological evaluation following partial nephrectomy diagnosed clear cell RCC. This case illustrates the potential of minor ALT elevations as early indicators of extrahepatic malignancies such as RCC. It emphasizes the importance of thorough evaluation for persistent, unexplained ALT abnormalities, particularly in patients with metabolic risk factors or past hepatic conditions. Increasing evidence suggests a possible pathophysiological link between RCC and liver enzyme alterations, including cytokine release and hepatic congestion. Future studies are warranted to investigate the predictive value of ALT as a biomarker for RCC and the role of inflammatory mediators such as IL-6 in RCC-associated liver function changes.