Dariusz Mazur was born on August 25, 1970, in Krakow.

He began his career in the justice system at the District Court for Krakow-Podgórze in Krakow, first as a legal assessor and later from 1998 to 2007 as a judge in the 2nd Criminal Division. Since 2007, he has been a judge at the Regional Court in Krakow. From 2010 to 2020, he chaired the 3rd Criminal Division of this court, also serving as the Coordinator for International Cooperation and Human Rights in Criminal Matters from 2017 to 2019. Since 2012, he has been a legal expert and lecturer in the "Linguistics" educational program organized by the European Judicial Training Network (EJTN). Previously, for seven years, he was a lecturer at the National School of Judiciary and Public Prosecution (2012-2019). He has authored numerous publications in Polish, English, German, and Czech.

In 2016, he was honored by the Polish Section of the International Commission of Jurists with the title "European Judge 2015" for justifying the decision declaring the inadmissibility of Roman Polanski's extradition to the USA. In 2020, he was awarded the Badge of Honor of the Polish Judges' Association "Iustitia" for activities related to presenting the current situation of the Polish judiciary worldwide.

He is interested in history, rock music, and one of the variations of Brazilian martial art, capoeira regional.