Born and educated in Scotland, John (Jock) Thornton served in the Royal Navy for 27 years where he specialised in nuclear submarine engineering. He was the marine engineer officer of two nuclear submarines and filled a number of shore appointments in subamarine training, operations and support before leaving the Service in 1989 to join the Australian Submarine Corporation. In his ten years with the corporation he filled a number of general manager positions including Integrated Logistics Support, Certification/Commissioing and Technical.
On leaving ASC in 1999, he joined the Malaysian company responsible for the management of the Royal Malaysian Navy's dockyard at Lumut and acted as their advisor on ship and submarine repair and maintenance.
On returning to Australia he was Engineering Manager at Tenix Marine in Williamstown before joining the University of Australia's Defence and Systems Institute in 2006.