D'Aloisio graduated from Monash University with a Bachelor of Arts and a Bachelor of Laws and was admitted to practice as a barrister and solicitor in Victoria, Western Australia, Queensland and the ACT, and as a solicitor in NSW.
D'Aloisio joined Mallesons in 1977. His main experience prior to that was principal legal officer with the Commonwealth Attorney-General's Department in the business and consumer affairs division in Canberra. Mr D'Aloisio practised as a commercial lawyer at Mallesons Stephen Jaques until taking up his role as chief executive in 1992. His principal areas of practice were mergers and acquisitions, taxation and restrictive trade practices, and international trade and investment. He was chief executive Partner at Mallesons between 1992 and 2004.
Before joining ASIC, Mr D'Aloisio held the position of Managing Director and Chief Executive Officer at the Australian Securities Exchange (ASX) from 2004 to 2006. During this time, he was also Director of the World Federation of Stock Exchanges. In addition to practising law, Mr D'Aloisio held a number of management and business positions within Mallesons, with his role involving extensive assessment of legal markets in Hong Kong and China, Thailand, Taiwan, Indonesia, Singapore, Malaysia, USA and the UK.
Mr D'Aloisio was Managing Partner of the Year in 2001 and in 2002 (Australian Law Awards). He also received the Australian Government Centenary Medal in 2000 for services to law and taxation.
He is also a director of the Business Council of Australia and a member of the Board of Taxation, the International Legal Services Advisory Council and the Chairman of its Globalisation of Legal Services Committee.