His fashion work is produced under his own label, The Ong, which is sold in Bloomingdale's and Bergdorf Goodman in New York City, and throughout Europe. Ong has also designed uniforms for the British Airports Authority, British Telecom, Raffles Hotel in Singapore, and he has remodelled the clothes of security staff at leading hotels in Beijing, ahead of the 2008 Summer Olympic Games. His private clients have included Princess Diana, the Duchess of Kent, Queen Noor of Jordan, and Shakira Caine. Ong is a graduate of London's Central Saint Martins and is a founding member of the London Designer Collections.
In the early 2000s, Ong made the switch from fashion designing to contemporary textile art. In 2007, he presented the exhibition Re-woven at the Singapore Art Museum. It comprised 46 pieces of silk textiles based on the art of Lao weaving. In 2015, Ong received the Singapore Design Golden Jubilee Award. In January 2016, Ong, in collaboration with a family of master Laotian weavers, presented The Pioneering Spirit at Raffles Hotel, an exhibition of 21 woven textiles, including the S$10,000 "The Shirt", featuring Lee Kuan Yew in his iconic white shirt in the shape of Singapore.
- Geoghegan, Tom (2007-06-27). "What not to wear at work". BBC News. Retrieved 2007-08-05.
- "HONG LEONG FOUNDATION SUPPORTS SPOTLIGHT SINGAPORE IN TOKYO" (PDF). Hong Leong Group. 2006-12-05. Retrieved 2007-08-05.
- Fang, Joy (19 January 2016). "Fashion designer turned textile artist Benny Ong weaves a playful nod to true craftsmanship". MediaCorp. TODAY. Retrieved 19 January 2016.