Dr Marx completed his medical degree at Stellenbosch University in 1996. After completing his internship, he worked as a junior medical officer (surgery and urology) at Livingstone Hospital and Port Elizabeth Provincial Hospital. During 1999 and 2000 he worked as a resident medical officer in the United Kingdom.
On his return to South Africa he worked as a senior medical officer (internal medicine) for 6 months, after which he commenced training as an anaesthetist. He obtained his Diploma in Anaesthesia in April 2001, whereafter he did anaesthesia locum work in the UK which included 6 months Critical Care training at Leicester General Hospital, United Kingdom. He completed his post graduate training at the University of Stellenbosch and qualified as a Consultant Anaesthesiologist in January 2007. Ever since he has been working as a sole proprietor in private practice in Cape Town and surrounding areas. His private practice encompasses all areas of anaesthesiology for all types of surgery.