Zak practiced at Sheffield’s Woodhouse Medical Centre for 23 years after qualifying as a doctor in 1988 and completing the Sheffield GP training scheme in 1993. In 1999 he was elected to the board of the South East Sheffield Primary Care Group. He acted as mental health and commissioning lead before taking over as PEC Chair. He moved to become Joint Medical Director of Sheffield Clinical Commissioning Group, eventually leaving his practice in 2014 to become sole Medical Director. With the abolition of CCGs in 2022 he became Sheffield place Medical Director within the South Yorkshire Integrated Care Board. Zak is a current member of the Quality Assurance Committee, Primary Care Commissioning Committee and the Sheffield Health and Wellbeing Board (which he co-chairs). He is a committed champion of NHS principles at the highest levels.