He debuted as a singer in Kraków's Zielony Balonik (Green Balloon) cabaret (1906) and as theater director in Warsaw's Polish Theatre (Teatr Polski, 1917).

He served as artistic director of the Ateneum Theatre (1932–34), raising its reputation as one of the leading voices for Poland's new intelligentsia in the interwar period.

In Lwów he developed his own concept of "monumental theatre," pertaining to the production of great Romantic works: Kordian (1930), Dziady (Forefathers' Eve, 1932) and Sen Srebrny Salomei (Salomea's Silver Dream, 1932).

On 29 June 1908 Schiller initiated a correspondence with the English actor, theater director, scenic designer, and theoretician of drama, Edward Gordon Craig.

[4] During World War II, as part of German repressive measures after the Volksdeutsch German-collaborator actor Igo Sym had been shot dead by the Polish underground (7 March 1941), Schiller was imprisoned at the Pawiak prison and at Auschwitz-Birkenau.