Dr Gannon is a general Obstetrician & Gynaecologist with an expertise in managing medical problems in pregnancy. He works in the Perinatal Loss Service at King Edward Memorial Hospital and is the RANZCOG nominee to, and Deputy Chair of, the Perinatal and Infant Mortality Committee in WA.

Dr Gannon is Immediate Past President of the Australian Medical Association (AMA). He sits on the National Health and Medical Research Council (NHMRC). He is a Board Member of MDA National Insurance. He is a former Chair of the AMA Ethics & Medicolegal Committee and a former President of AMA WA (2014-2016).