He further advanced his skills in plastic surgery training at the Department of Plastic Surgery, University of Tokyo, Japan & the Taipei Chang Gung Hospital in Taiwan. He worked in the Department of Plastic Surgery in Singapore General Hospital from 1986 to 1995 before he began his private practice at the Gleneagles Medical Centre. He is now located at Mount Elizabeth Novena Specialist Centre.

Dr Leslie Kuek is a key figure in the development of plastic surgery in Singapore. He was instrumental in developing the Breast Reconstruction & Facial Paralysis Reconstruction programs in the Department of Plastic Surgery at the Singapore General Hospital. Additionally, he was also a clinical teacher and lecturer in Plastic Surgery to surgical trainees, medical students and nurses.

As a senior member of the plastic surgery community, Dr Kuek is much sought after by TV and Radio Media, as well as local and foreign magazines for his opinions and ideas on issues pertaining to the field of Plastic & Cosmetic Surgery. He has given, and continues to give numerous lectures and seminars on Plastic Surgery both in Singapore and overseas.

Some of the publications Dr Kuek has been featured in include Her World, Female Dare, Cream, Prestige, Next Magazine (Hong Kong), The Singapore Women’s Weekly Asiaweek, The Straits Times, Lian He Zao Bao, Lian He Wan Bao, Crew Magazine, Indonesia Tatler, THIS Quarterly: Timely Health Information & Style.

In 2002, he led a volunteer team of Singaporean doctors and nurses to Indonesia to help treat victims of the Bali bomb blast. He also participated in the Parkway medical relief mission to Sri Lanka in the aftermath of the Tsunami in December 2004.

He has held various positions, serving as the president of the Singapore Society of Cosmetic (Aesthetic) Surgeons, and Singapore Association of Plastic Surgeons.