From 1994 to 2001, he was managing director of Yenom Holdings Pte Ltd. Both Liang Court and Yenom Holdings belonged to billionaire Goh Cheng Liang. On 1 March 2001, he was elected as an independent director to the Board of Tung Lok Group.[2] He was chairman of Superior Metal Printing Limited (1990–1992, Sep 1994–1995); deputy chairman of the Chinese Development Assistance Council (Sep 1994–2000).[1]
Ker entered politics through a walkover in Aljunied GRC in the 1991 General Election.[3] In the 1997 General Election, the PAP team faced opponents from the SDP and won 67.02% of the votes.[4] He was Minister of State (Sep-Dec 1991) and later Minister of State for Education (Jan 1992) and Information and the Arts (Jan 1992-Aug 1994).[1] Ker was the chairman of the Aljunied Town Council (Feb 1995) and the Government Parliamentary Committees for Home Affairs and Law (Aug 1995–1996).[5] He stepped down from politics at the 2001 General Election.
From October 2002 to June 2007, he was appointed Trade Representative in the Singapore Trade Office in Taipei.[6] From July to December 2007, Ker was the special adviser to Minister for Foreign Affairs George Yeo, who was his Aljunied GRC teammate. Ker was the Consul-General in Hong Kong and Macao between 2008 and 2012.[5]
Ker presently serves as adjunct professor at Lee Kuan Yew School of Public Policy, National University of Singapore,[7] and at the Public Policy and Global Affairs programme of Nanyang Technological University.