His grandfather, Ong Ewe Hai was a prominent Kapitan Cina to the Hokkien community of Sarawak, and a successful businessman in multiple fields.
His eldest brother Hap Hin passed on at a very young age due to illness, resulting in Ong becoming the patriarch of the family as soon as he was eligible.
In 1947, the Colonial Government appointed him as one of the Kapitan Cina representing the Hokkien community, succeeding his father, Ong Tiang Swee who later passed on in 1950.
He also established a business enterprise named Hiap Soon Hin at the Main Bazaar, the earliest and oldest agent for AIA Insurance, until he gave it up in the 1970s.
There are a total of six roads in Kuching, Sarawak named after generations of the Ong family, mostly by the Rajah in recognition of their contribution to the community.