When Szlechter was 14 years old, he joined the Małopolskie Oddziały Armii Ochotniczej (Lesser Poland's Volunteer Army) and during summer 1920 he participated in the defense of Lwów.
His earliest lyrics were written for Leon Borunski's songs, staged at the Morskie Oko theater's Parada gwiazd show in 1930, performed and recorded by Syrena Rekord star Kazimierz Krukowski.
He made a series of "Jewish" records including like Awremałe (Avremele), Śpiewak sobotni, Rabi Eli-Melech (Rabbi Elimelech), Alef Bet (Oyfn Pripetchok), and Żydowskie wesele (Yidishe khasene).
[5] He wrote lyrics of many songs featured in Polish pre-war films including Parada rezerwistów, Kobiety na sprzedaż, Trójka hultajska, Kocha, lubi, szanuje, Czy Lucyna to dziewczyna?, Co mój mąż robi w nocy, Jaśnie pan szofer, Dodek na froncie, Jego wielka miłość, Skłamałam, Książątko, Wyrok życia, Robert i Bertranda, and Czarna perła.
Some of his hits included: In September 1939, during the German and Soviet invasion of Poland Schlechter was working at the Lwów Teatr Miniatura as an actor, writer and director.