Sonny was born on 13 August 1941 in Kuala Lumpur, Malaysia.

He had his primary, secondary and tertiary education in Malaysia and the United Kingdom, graduating as an architect in 1963 at the Northern Polytechnic of London, and did post graduate Tropical studies at the Architectural Association School in 1964.

Thereafter, Sonny practiced in London with Arup Associates. He returned to Singapore in 1965 to continue his practice with Kumpulan Akitek, and established his present practice under the style of Chan Sau Yan Associates in 1993 after 29 years of practice in his previous firm leaving as a Senior Partner. In 2011, Chan Sau Yan Associates has been incorporated and now known as CSYA PTE LTD.

Sonny experience encompasses a wide range of residential, commercial, institutional, recreational and tourism related projects in the region as well as internationally. His extensive experience in resorts and city hotels span over more than 45 years working with international chain operators such as Hyatt, Sheraton, IHG, Mandarin Oriental, Hard Rock Hotel, Hilton and other independent operators.

Besides practice, Sonny was a founder member of the Singapore Planning and Urban Research Group. He has also been an external tutor, examiner and adjunct associate professor in the School of Architecture, National University of Singapore, external critique with Universiti Malaya as well as serving in the professional institute and other government institutions, acting in various capacities.

He has received several architectural awards for design distinction, among others the prestigious President’s Design Award 2011 in the Designer of the Year category.