Tumor lysis syndrome (TLS) is a life-threatening oncologic emergency that occurs due to the rapid lysis of malignant cells, leading to severe metabolic disturbances. This case describes an 80-year-old male with chronic lymphocytic leukemia (CLL) who was admitted for initiation of cancer therapy and subsequently developed TLS. The pathophysiology of TLS involves hyperkalemia, hyperphosphatemia, hypocalcemia, and hyperuricemia, all of which contribute to complications such as acute kidney injury, cardiac arrhythmias, and neuromuscular dysfunction. Staging of CLL using the Rai and Binet systems plays a crucial role in treatment decisions, guiding the use of therapeutic agents such as purine analogs, alkylating agents, monoclonal antibodies, and small molecule inhibitors. Preventative and management strategies for TLS, including aggressive hydration, uric acid-lowering therapies, electrolyte correction, and renal replacement therapy, are critical to improving patient outcomes. This case underscores the importance of early recognition and intervention in a high-risk patient.