He received international recognition for portraying Moritz Welt in Andrzej Wajda's drama film The Promised Land.

He gained international visibility following Andrzej Wajda's 1975 film The Promised Land, in which he played Moritz, one of the three main characters.

[1] The actor left Poland during the period of political unrest in 1980–81, when the Solidarity trade union began and was ended by the imposition of martial law on 13 December 1981.

Pszoniak did not speak French when he emigrated to France, so he learned his theatrical lines phonetically; in movies like Danton, where he played Robespierre, his voice was dubbed.

[4] In 1990, Gustaw Holoubek ranked Pszoniak among the three greatest Polish dramatic actors post-1965 alongside Andrzej Seweryn and Piotr Fronczewski.