[2][3] Oon spent part of her childhood in London where her father worked as an executive at Royal Dutch Shell.
[5] After graduating from the University of Singapore, Oon was a features and music journalist for the New Nation newspaper.
[2][5] In 1974, she began a food column in New Nation at the request of her then-editor David Kraal.
[11][12] From 2017 to 2019, Oon and her children opened three more restaurants in Clarke Quay, ION Orchard, and Jewel Changi Airport which focus on Peranakan as well as British-Hainanese cuisine.
[2][4][7] In 1995, Oon began operating a food consultancy business that served several major events in Singapore such as the 2006 meeting of the International Monetary Fund and World Bank Group.
[9] She led Singaporean teams at the World of Flavors Conference and Festival organised by the Culinary Institute of America in 2004, 2007, and 2009.