Dr Ranjan completed formal surgical training in New Zealand followed by specialised training in Christchurch and Australia. He focuses on bariatric, gastrointestinal, general, and trauma surgery, and is recognised for his high level of skill, expertise, communication and calm manner.

He practices in both the public and private sectors and volunteers with Canterbury Charity Hospital. His approach emphasises tailored solutions, with an objective to enhance patient care, promote healthy lifestyle changes, and ensure patients feel confident, supported, and heard when managing their health.