David was admitted as a solicitor in 1974, and was first called to the Bar in 1977.

David is admitted to practise in Australia, England and Wales (where he is a member of Lincoln's Inn), the Courts of the Dubai International Financial Centre, New York (Legal Consultant), New Zealand, the Singapore International Commercial Court and Papua New Guinea. He was first appointed Queen's Counsel in 1986.

David has lectured at the University of Sydney for the Master of Taxation course, the University of Queensland for the Master of Laws course and served as an Adjunct Professor of the University of Queensland. He is the co-editor of the Oxford University Press Journal Trusts & Trustees.

He was the inaugural Chairman of the STEP International Client Special Interest Group, a director of STEP (and, for 2018, Deputy Chair) and a member of its World Wide Council and various Committees, a co-chair of the United Arab Emirates Chapter of the International Section of the New York State Bar Association, and a member of the Executive Committee of the Section, an Academician of The International Academy of Estate and Trust Law, a Member of the Middle East and North Africa Branch Committee of the Chartered Institute of Taxation (UK), a member of the Worshipful Company of Tax Advisers, a Freeman of the City of London and an Honorary Member of the Taxation Institute of Hong Kong. From 2016, he has chaired the DIFC's Wealth Management Review Working Group.

In 2010, David was awarded the Order of the Rising Sun (with Gold Rays and Neck Ribbon) for his services to Australia-Japan relations. In 2012, he was appointed a Member of the Order of Australia for, among other things, “service ... to taxation law and legal education".