Ong was a member of the
Perak State Legislative Assembly for
Chenderiang for four terms from 1986 to 2004, 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. Despite this, he was appointed MCA secretary-general the following year and served concurrently with his brother
Ong Ka Ting as president. In 2009, he was dropped from the Cabinet by incoming Prime Minister
Najib Razak. In the
2013 general elections, Ong successfully defended his parliamentary seat despite MCA suffered its worst electoral result in its history. As a result of MCA poor performance and its previously passed resolution not to take up cabinet posts in the government if it failed in the 13th general election, MCA will not take up any government position. Later in 2013, MCA elected
Liow Tiong Lai as the new president and reversed its resolution. Liow appointed Ong as new MCA secretary-general for the second time then. ==Election results==