Jon commenced working for national park agencies throughout Australia in 1975; in 1986, he joined the Great Barrier Reef Marine Park Authority. For the following 28 years, he was involved in many aspects of planning and managing the Great Barrier Reef. For the last 16 years of his career, Jon was one of the Directors at GBRMPA, variously responsible for biodiversity conservation, park planning, heritage (particularly World Heritage), Indigenous Partnerships, the GBR rezoning and commencing the first GBR Outlook Report. He retired in 2014 and has become more involved in developing the Climate Vulnerability Index (CVI), a rapid assessment tool being applied in many World Heritage properties.