Mr Gerrard trained at King's College Hospital in London, having qualified in 1989. His first job as a doctor was at The Royal Surrey County Hospital where he developed his interest in surgery. His higher surgical training was in the South West Thames region and at St Thomas' Hospital, London, where he completed a fellowship in endovascular aortic surgery. Following, he was appointed consultant at Frimley Park Hospital and received an honorary contract to provide vascular surgery at The Royal Surrey in 2001. He introduced endovascular treatment of abdominal aortic aneurysms to the hospital together with radiology colleague Andrew Hatrick. The programme has now treated over 400 aneurysms. In 2011, Mr Gerrard and Mr Hatrick developed the first endovascular programme to treat complex aortic aneurysms in Surrey.
Mr Gerrard is interested in a wide range of vascular diseases and started the endovascular program in West Surrey in 2004. They were one of the first groups in this country to treat varicose veins with lasers (EVLT). Together as part of the Surrey Vein Clinic, they have performed over 3000 procedures.
Other notable achievements are setting up a multidisciplinary diabetic foot service at Frimley Park Hospital in 2003 and his role as a Training Programme Director in Kent Surrey and Sussex for core and higher surgical trainees.