After completing his studies at the Methodist Boys’ School in Kuala Lumpur, Malaysia, Cheong obtained a Bachelor of Science with First Class Honours in Mathematics from the University of Adelaide in 1964. He studied in Australia as a Colombo Plan scholar.

He left academics in 1974 to work with Singapore Airlines. He spent 29 years at Singapore Airlines; he eventually became the company’s CEO.

In 1998, Fortune named him Asian Businessman of the Year, noting that SIA had an “unbroken 27-year record of profitability through turbulent economic times.”

He was first appointed to the board of OCBC on 1 July 1999. He served as vice chairman from 26 March 2002 to 30 June 2003. On 1 July 2003, he was elected chairman of the board.

He served as Chairman of the Singapore Broadcasting Corporation and of its successor, Singapore International Media from July 1989 to September 1995. He has also served as the Chairman of the Council of the National University of Singapore. His service was for two consecutive two-year terms ending on July 31, 2004. He has served as Vice-Chairman of the Singapore-US Business Council. Finally, Cheong has held directorships in companies which include Singapore Press Holdings Ltd, Great Eastern Holdings Ltd and United Eagle Airlines Co Ltd.

In February 2018, BRIEF-Frasers Centrepoint Trust announced the appointment of Kong as the new chairman.