Mr Rajan graduated from the University of Cambridge in 2000, and trained in surgery in the East of Scotland. In 2005, he commenced a 3-year full-time PhD in prostate cancer genetics at Newcastle University funded by a prestigious Medical Research Council Clinical Research Training Fellowship. He moved to the West of Scotland for urology training, focussing on complex cancer surgery, and obtained urology specialist registration in 2014. In parallel, as a Clinical Lecturer at the University of Glasgow, he continued post-doctoral research at the Cancer Research UK (CR-UK) Beatson Institute. He was the first urologist in Scotland to win a highly-competitive Royal College of Surgeons of England/CR-UK Clinician Scientist Fellowship in Surgery to support his research into prostate cancer.

Mr Rajan undertook a clinical and research fellowship in robotic "keyhole" prostate cancer surgery at the Karolinska Institutet and University Hospital, Stockholm, Sweden. On his return to Glasgow in 2015, he was appointed as a Consultant Urologist specialising in laparoscopic "keyhole" kidney cancer surgery. The same year, he was recruited to St. Bartholomew's Hospital (Barts Health NHS Trust) and University College London NHS Foundation Trust, London, UK. He currently specialises in robotic prostate cancer and complex advanced testicular cancer surgeries. Mr Rajan leads an internationally-renowned laboratory-based research group at the Barts Cancer Institute, Queen Mary University of London and runs clinical trials to find new ways to treat prostate and testicular cancers. 

Mr Rajan holds Fellowships of the Royal College of Surgeons of England, the Higher Education Academy, and the Alan Turing Institute. He is a member of the National Cancer Research Institute Advanced Prostate Cancer and Germ Cell Tumours Research Groups. He is also an Associate Professor of Urology at University College London (UCL) and sits on the UCL Urology Clinical Academic Board. ​

In his spare time, Mr Rajan enjoys cycling and running. He seeks the challenge of visiting exotic off-the-beaten-track locations, particularly where he can practice his language skills in Tamil, and to a lesser extent Hindi and Spanish.