The Hon Alan Robertson is a graduate of the ANU. He was admitted in 1980 as a legal practitioner of the Supreme Court of the Australian Capital Territory. From 1981 to 1983, he worked as assistant to the Commonwealth Solicitor-General, Sir Maurice Byers. 

In 1983, Justice Robertson moved to the New South Wales Bar and, in 1995, was appointed Senior Counsel. His area of specialisation was public law, including constitutional and administrative law, revenue law, competition law and appeals. He was for many years convenor of the Constitutional and Administrative law section of the New South Wales Bar Association. He was a part time member of the Administrative Review Council between 1992 and 1997. 

He was appointed a judge of the Federal Court in April 2011, based in Sydney. He has been appointed a Deputy President of the Administrative Appeals Tribunal and a Deputy President of the Australian Competition Tribunal.  He is the Deputy President of the Australian Academy of Law.