Dr Shannon commenced practice as a consultant physician in Orange in 1980 helping establish dialysis facilities and diabetic education services for the district in the early 1980’s.

A Director of Physician Training at Orange Hospital from 2001 until 2016. With the establishment of Sydney University’s School of Rural Health in Orange and Dubbo in 2001 he was appointed Deputy Head of the School.

In 2001 he was appointed Senior Staff Specialist at Orange Hospital and became the inaugural chair of the Patient Safety and Clinical Quality Committee Orange Hospital and in 2005 Clinical Leader Clinical Governance Unit WNSWLHD. Previously a Board Member of the Clinical Excellence Commission and the Agency for Clinical Innovation from 2008 until 2016.

He was named Collaborative Leader of the Year NSW Health [inaugural presentation] in 2013 and awarded the Royal Australasian College of Physicians Medal for Clinical Service in Rural and Remote Areas in 2014.