Jark did basic medical training at the State University of Ghent and obtained his MD in 1990. His postgraduate training was based in England. This included a year of training in the West Midlands Centre for Spinal Injuries, followed by six months of training in neurology at the Walton Centre for Neurology and Neurosurgery in Liverpool. Jark then joined the Spinal Surgery Unit at the Robert Jones and Agnes Hunt Orthopaedic Hospital in Oswestry.
Following completion of basic surgical training Jark passed the FRCS examination in Edinburgh in 1995. After this he entered the neurosurgical training program at the Walton Centre and passed the neurosurgical specialty examination in 2000. Jark worked briefly in Spinal Orthopaedic surgery in Zurich (Switzerland) in 2001. This comprehensive training gave him a wide experience in Orthopaedic and Neurosurgical Spinal Surgery. From 2002 he has worked as Consultant Spinal Neurosurgeon and Honorary Senior lecturer in Neurosurgery.