Between March 1994 and August 2000, Mr Cheung was the Chief Executive of Hongkong Telecom, a publicly listed company in Hong Kong with 16,000 staff and a market capitalization of US$25 billion. Hongkong Telecom was a subsidiary of Cable & Wireless plc and Mr. Cheung was the first Chinese Executive Director of Cable & Wireless plc in the United Kingdom which had a long history.

Mr Cheung led Hongkong Telecom and successfully transformed it from a monopoly to a highly competitive and customer-driven company. In June 1997, he introduced Chinese shareholding into Hongkong Telecom. In February 1998, he successfully negotiated an early termination of the company’s exclusivity rights with the HKSAR Government and Hongkong Telecom shareholders received a HK$12 billion compensation package of which HK$6.7 billion was in cash. In August 1998, Mr Cheung was the first CEO of a leading Hong Kong corporation to initiate salary cuts across the board for all 16,000 Hongkong Telecom staff to avoid massive layoffs.

Before joining Hongkong Telecom in 1994, Mr Cheung served 23 years with Cathay Pacific Airways, a subsidiary of the Swire Group. He left Cathay Pacific Airways in 1994 as Deputy Managing Director. After Hongkong Telecom's merger with PCCW in August 2000, he became its Deputy Chairman and served until February 2004. He was also Chairman of Asia Television Ltd. from December 2008 to December 2009.

Between 1989 and 1990, Mr Cheung was seconded full time to serve in the Hong Kong Government’s Central Policy Unit under Governor David Wilson’s administration. He was appointed an Official Justice of the Peace in 1990 and a Non-official Justice of the Peace in 1992.

In 1999, Mr Cheung was awarded “Executive of the Year for Hong Kong” by DHL/South China Morning Post. He was also twice elected as the “Best Telecom Chief Executive in Asia” by the magazine Telecom Asia for the years 1998 and 1999.

For many years, Mr. Cheung was a member of the Council of The University of Hong Kong. He was the Chairman of the Board of Directors of The University of Hong Kong School of Professional and Continuing Education which has over 110,000 student enrolments every year, and was the Chairman of the Council of Centennial College, which is a member of The University of Hong Kong Group. Mr Cheung is an independent non-executive director of China Unicom Limited, since May 2004. He is also an independent non-executive director of Hong Kong Resort International Ltd. Mr. Cheung was an independent non-executive director of Tai Kang Life Insurance in China.

Mr Cheung received a BSocSc degree with Honours and a Diploma in Management Studies with distinction from The University of Hong Kong. He is an Honorary Fellow of The University of Hong Kong and of the Chartered Institute of Marketing, UK. He is very active in public services and hosted a very popular radio programme on Radio & Television Hong Kong from 2003 to 2013. He was an Adjunct Professor of the Chinese University of Hong Kong.  He is also a well known art connoisseur.