[1] Ong was the secretary-general for twice for the Malaysian Chinese Association (MCA), a component party of the Barisan Nasional coalition.
Ong was a member of the Perak State Assembly for Chenderiang for four terms from 1986 to 2004,[9] before contesting the federal seat of Batu Gajah in the 2004 general election.
He lost to Fong Poh Kuan of the Democratic Action Party (DAP), despite the Barisan Nasional coalition making widespread gains nationwide.
[13] In the 2013 general elections, Ong successfully defended his parliamentary seat despite MCA suffered its worst electoral result in its history.
[4][6] In 2015, Najib Razak in a cabinet reshuffle eventually appointed Ong as the Second Minister for International Trade and Industry.