As the first general director of the theatre Václav Jiřikovský decided in 1920, operetta company was cancelled for a short period. However, since the 1923/1924 season, all the titles that operetta company introduced have been forming crucial part of the repertoire. Despite this fact, the company was formed by opera ensemble reinforced with drama actors and soloists until 1944.
Quality of the ensemble was strengthened by piano player and conductor Vladimír Brázda, by actor and director Jan Pacl, and by actor Josef Kobr, who have been forming the evolution of the company after the war. At this time, the Ostrava music ensemble belonged to the best Czech ensembles in which Liběna Astrová, František Návrat, Karla Diváková, Karel Čepek or Miloslav Tolaš excelled. Musicals occurred in the repertoire more and more often in the 60s. When the company was led by Mojmír Weimann (1971–1981), many Czechoslovak premieres were introduced. In the 80s, when the ensemble was led by Josef Kobra, the repertoire contained classical operettas as well as Czech and foreign musicals.
It was in 2010 when musical became a part of the company’s official name. Since then, its name is Operetta/Musical. Also, the repertoire includes contemporary world-known and Czech musicals. Nowadays, there are four Thalia Award holders in the company: Hana Fialová, Tomáš Savka, Lenka Pavlovič, Katarína Hasprová and Martina Šnytová. The greatest achievement of the ensemble in its hundred-year-long existence is the guest performance in Daegu, South Korea, during DIMF festival in 2015. The company introduced Radim Smetana’s The Phantom of London which was created for the National Moravian-Silesian Theatre and its opening night took place at the Jiri Myron Theatre in May 2013. On July 13, 2015, the musical was awarded three times, including the award for the best musical of DIMF festival! It was for the first time in history of the theatre when one of its four ensembles performed outside the European continent.
Currently, head of the Operetta/Musical company is Gabriela Petráková.