Born 1947 in Ljubljana (Slovenia), Marko Ilešič obtained a law degree at the Faculty of Law of the Univerza v Ljubljani(University of Ljubljana, Slovenia) in 1970 before studying for a doctorate at that same university, where he presented his thesis in 1984. He furthered his knowledge of comparative law in specialist programmes organised by the université de Strasbourg (University of Strasbourg, France) and the Universidade de Coimbra (University of Coimbra, Portugal), graduating from those universities in 1978 and 1980, respectively.

He began his academic career in 1970 as a lecturer at the Univerza v Ljubljani, where, as a professor, he taught civil law, commercial law and private international law from 1984 to 2004. In addition, he played an active role in the management of the Faculty of Law of the Univerza v Ljubljani, serving in that faculty as Vice-Dean from 1995 to 2001 and, subsequently, as Dean from 2001 to 2004.

After passing the judicial service examination, Mr Ilešič became a judge and, subsequently, President of Chamber at the Sodišče združenega dela v Ljubljani (Labour Court, Ljubljana, Slovenia) from 1975 to 1986. An author of numerous publications, he was elected as President of the Union of Slovene Lawyers’ Associations in 1993, an office which he held until 2005.

A strong interest in sports law and in particular in football also led him to serve as President of the Sodišče združenega dela za telesno kulturo (Sports Tribunal of Slovenia) from 1978 to 1986 and as a judge on the Boards of Appeal of the Union of European Football Associations (UEFA) and of the International Federation of Association Football (FIFA). Furthermore, he took on managerial duties as President of the Nogometna zveza Slovenije (Football Association of Slovenia) from 1985 to 1989, as President of the Football Association of Yugoslavia between 1990 and 1991 and as a member of the Executive Board and, subsequently, as Vice-President of the Olympic Committee of Slovenia from 1991 to 2005.

Holding a particular interest in the practice of commercial law, he was President of the Arbitration Chamber of the Ljubljana Stock Exchange and an arbitrator at the Chamber of Commerce of Yugoslavia. He was then an arbitrator at the Chamber of Commerce of Slovenia and at the International Chamber of Commerce in Paris.

Judge at the Court of Justice from 11 May 2004 to 20 June 2024, the date of his death.