Born in 1974 in Prague (Czechoslovakia), Mr Jan Passer studied at the Universita Karlova (Charles University, Czech Republic) where he obtained his law degree. He also completed a Masters of Laws at the Stockholms universitet (University of Stockholm, Sweden) in 2000. In 2007, he defended his doctoral thesis in law at the Universita Karlova.

Since 1997, he carried out a number of judicial functionsin his home country, first as a trainee judge at the Městský soud v Praze (Prague City Court, Czech Republic), a position which he held until 2001, and then as a judge at the Obvodní soud pro Prahu 2 (Prague 2 District Court, Czech Republic), from 2001 to 2005. From 2005 to 2016, he was a judge at the Nejvyšší správní soud (Supreme Administrative Court, Czech Republic).

The substantial experience gained during his practice took Mr Passer to teaching. He was a lecturer in, amongst other subjects, EU law at the Universita Karlova from 2001 to 2003, at the Masarykova univerzita (Masaryk University, Czech Republic) from 2006 to 2016, and at the Univerzita Palackého v Olomouci (Palacký University Olomouc, Czech Republic) from 2014 to 2016. That expertise also led him to teach law at the Judicial Academy of the Czech Republic from 2001 to 2016.

Mr Passer was appointed as a Judge at the General Court of the European Union on 19 September 2016. He served at the General Court for four years before being appointed, on 6 October 2020, to his current role as a Judge at the Court of Justice.