Niedziałkowski acted internationally as part of the company until 1975, before moving on to co-found and co-create “The Stage of Mimes” at The Warsaw Chamber Opera.
Marcel Marceau wrote the foreword to the book, concluding "...Stefan has opened the door with utmost sincerity and integrity, and his contribution is beyond words."
In 2005, Stefan Niedziałkowski's Mimes Studio moved to its current location at the Mazovia Region Centre of Culture and Arts in Warsaw.
As a part of the celebration, Stefan Niedziałkowski created, directed, and choreographed his mime drama, “Dusioł” (Soul), for the Wrocław Pantomime Theatre company.
Niedziakowski played the title role as a guest artist at the premiere in December 2006 on the Scena Kameralna of the Polish National Opera in Warsaw.