In his early career he worked as a lyric tenor but as he aged his voice developed into Heldentenor which enabled him to become a celebrated performer in the operas of Richard Wagner.
[2] Beirer made his professional opera debut at the Linz State Theatre in 1936;[1] performing the role of Hans in Bedřich Smetana's The Bartered Bride.
In the early years of World War II (WWII) he was in Hanover, Germany as a resident artist at the Mellini Theatre where he starred in operettas from 1939 until 1941 when he was conscripted into military service.
While working for the military he was still able to perform periodically in operettas in Berlin at the Neues Schauspielhaus where his repertoire included the roles of Danilo in The Merry Widow and Barinkay in The Gypsy Baron.
[2] He also made just one appearance at the Deutsche Oper Berlin (DOB) during the war; making his debut at that opera house as Nando in Tiefland in 1943.
[2] Other roles he performed from the dramatic tenor repertoire at the DOB included Bacchus in Ariadne auf Naxos,[1] Florestan in Fidelio,[2] Pedro from Tiefland,[2] Radames in Aida,[1] and Vasco da Gama in L'Africaine.
In 1949 he made his debut at the Teatro di San Carlo as the Drum Major in Alban Berg's Wozzeck, and sang the title role in Parsifal with Maria Callas and Cesare Siepi as his co-stars.
[1] He later returned to La Scala in 1952 to sing the part of Walther von Stolzing under conductor Wilhelm Furtwängler, and was again heard at that opera house as Tristan (1957) and Tannhäuser (1967).