He was educated at St. Joseph's College, Hunters Hill, where he won the Lawrence Campbell Oratory Competition in both 1953 and 1955, before matriculating to receive first class honours degrees in Arts and Law from the University of Sydney.

Among his graduating class of 1962 were John Howard, later to become Prime Minister; and Michael Kirby, who later served alongside him as a judge on the High Court.

His appearances as junior counsel focussed mainly on matters of taxation and commercial law, as well as important constitutional cases including Strickland v Rocla Concrete Pipes Ltd, which concerned the scope of the corporations power.

However he also appeared in some high-profile criminal cases, including his successful defence before a jury of National Party MP Ian Sinclair in 1980.

[3] In the same year he appeared for the appellants in Port Jackson Stevedoring v Salmond & Spraggon, the last case granted leave to appeal to the Privy Council from the High Court.

During Gleeson's decade as Chief Justice of New South Wales, the court system dealt with considerable change including fast growing demand, cost constraints and delays.

He sought to delineate appropriate boundaries for the political debate surrounding litigation, and was adamant that the proper administration of justice was a part of civilised government and not a free market privilege.

During his tenure as Chief Justice, Gleeson actively maintained the importance of judicial independence in the face of increasing executive government power and public anger with court decisions.

On 7 November 2008, Gleeson was appointed a non-permanent judge of the Court of Final Appeal of the Hong Kong Special Administrative Region and served until 29 February 2024.

Their eldest daughter, Jacqueline, was appointed a judge of the Federal Court of Australia in 2014, after practising law as a barrister at the Sydney Bar and as general counsel of the Australian Broadcasting Authority.