Greenwood was made an Honorary Member of the Order of Australia on 17 October 2003 as part of a special honours list for providing medical assistance to victims of the 2002 Bali bombings. His career has been in treating acute burns patients. He has developed new techniques and skin substitutes to treat severe burns. He was awarded Doctor of Health Sciences in 2013 for a thesis documenting the establishment of the Adult Burn Service in South Australia.He retired in October 2020.