William was born in Penang, Malaysia and learnt to speak and write Bahasa Malaysia in school. When he was growing up in Kuala Lumpur, the dialects of Hokkien and Cantonese were spoken at home, and he was tutored for a couple of years in Mandarin.
William also contributes to legal education. He has instructed at Leo Cussen Institute since the late 90s in Commercial and Corporate Practice, and Retail Leases. He is the Chief Moot Coach at Monash University Law School teaching the subjects of Mooting and Advocacy Competition and Jessup Moot Competition. He also teaches Contract Law and Property Law as a Special Sessional Lecturer. He is an appointed Adjunct Professor at the Faculty of Business and Law, Swinburne University of Technology, and an Adjunct Fellow at the Sir Zelman Cowen Centre.
William is a founding member and the Immediate Past National Vice President of the Asian Australian Lawyers Association. He is also one of the Honorary Patrons of the North American Australian Lawyers Alliance Incorporated.
On Australia Day 2017, William was awarded the Order of Australia Medal for ‘service to the law, to business, and to the promotion of cultural diversity’. In the same year, at the 2017 Lawyer's Weekly Australian Law Awards, he won the Barrister of the Year Award and the Excellence Award.
William serves on the national board of The Order of Australia Association Limited as Deputy National Chairman. He is one of the Australia Day Ambassador for Victoria. He is also on the Council of Swinburne University of Technology.