Trained as a general surgeon, Dr Mack has been working in a public hospital for more than three decades and instrumental in pioneering laparoscopic surgery for the hospital in the early 1990's. Part of his career involves leading a medical research team in an experimental laboratory for about seven years. Thereafter he participated in the field of quality assurance in healthcare policy before returning full time to clinical work and help shaping postgraduate medical education. Thereafter he became involved in  developing medical simulation for medical residency training. 

Apart from basic medical degree and Fellowships from the Royal Colleges of Surgeons of Edinburgh and Glasgow, he has other non-medical qualifications. He completed his MBA (NUS), Master in Health Economics (Curtin) and Master in Medical Education (Dundee). He has also received his PhD in Medical Science from Lund University, Sweden. He has authored many scientific publications, several books and book chapters. In recent years he has developed an interest in hypnotherapy and developed a practice in regression therapy to complement his mainstream clinical work. His latest book publications reflect his contribution in the use of regression therapy within his medical practice.