Joanna Leszczyńska studied law at the Faculty of Law of the University of Białystok from 2005 to 2010. In 2012, she graduated in international relations from the Faculty of History and Sociology of the University of Białystok.
Between 2010 and 2013, she worked i.a. as an academic teacher, teaching administrative law.
Since February 2013, she is a member of the Local Government Appeal Board in Jelenia Góra. From 2014 to 2017, she worked as an assistant judge at the Wrocław District Court.
In 2016, she defended her disseration on spatial planning and development, obtaining a doctoral degree in law in the discipline: law, with specialisation in administrative law.
Since 2017, she has been registered on the list of attorneys-at-law at the Wrocław Bar Association.