Simon Wessely was appointed to the JAC as a lay member on 1 September 2017.

Simon is Regius Professor of Psychiatry at the Institute of Psychiatry and Neuroscience at King's College London. He is an honorary consultant psychiatrist at King's College Hospital and the Maudsley Hospital, a civilian consultant advisor in psychiatry to the British Army and Director of the King's Centre for Military Health Research. He is President of the Royal Society of Medicine and a former President of the Royal College of Psychiatrists.

Simon is also a Trustee of Combat Stress and has campaigned to improve the understanding and image of mental health. He was awarded a knighthood for services to military healthcare and to psychological medicine.