Gouldthorpe grew up in Sydney where he studied art at East Sydney Technical College in 1971-1972. He moved to Tasmania in 1973 and taught painting, drawing and printmaking part-time at Devonport and Launceston TAFE Colleges from 1975 to 1988. For his art he uses a diversity of mediums such as pencil, coloured inks, watercolour, and acrylic paint, and he is one of the few children's book illustrators who has also used printmaking techniques such as linocuts in his work.
In 2011, Lothian published Gouldthorpe's account of British polar explorer Robert Scott's Antarctic expeditions.