Dr. Miljko earned his Bachelor’s degree in law from the University of Mostar in 1980. Не then earned his Master’s degree in constitutional law at the Law Faculty in Belgrade. Не was awarded a PhD from the Ј. Ј. Strossmayer University in Osijek, for his thesis on the constitutional development of Bosnia and Herzegovina.

Не was an associate professor at the State Law Sciences Department of the Law Faculty at the University of Mostar. He is the author of the book Ustavno uređenje Bosne i Hercegovine (2006) and has also authored many papers under the theme of constitutional law in national and international magazines, addressing topics such as federalism, human rights and freedoms, constitutional judiciary and the election system. Не participated in numerous national and international scientific gatherings. Before being elected a Judge of the Constitutional Court of Bosnia and Herzegovina, he held important positions. He was a member of the Legislative Commission, member of the Constitutional Commission of the Parliament of the Federation of Bosnia and Herzegovina, and а representative in the Assembly of Herzegovina-Neretva Саntоn.

He served as a Judge of the Constitutional Court of Bosnia and Herzegovina from May 1997 to May 2002.