Anton Haizinger heard Haizinger sing in concerts, and offered him an engagement at the theatre; Haizinger gave up teaching. Haizinger's first roles at Theater an der Wien, in 1821, were in two operas by Rossini, as Gianetto in "La gazza ladra" and Lindoro in "L'italiana in Algeri". He soon became well-known in Vienna. The role of Adolar in Weber's opera "Euryanthe", premiered in 1823 at the Theater am Kärntnertor, was created for him, and he was a soloist in the premiere in 1824 of Beethoven's Ninth Symphony at the same theatre. He continued studies with Antonio Salieri. At this time, Italian opera
Rudy La Scala under the name Flavio, released the song "Piensa, Sueña y Rie". Three years later, he changed his name to Rudy La Scala and presents the song "Woman", issued in Venezuela, Brasil, France and South Africa. The following year, La Scala recorded in Italy an album with Vittorio De Scalzi, the lead singer of the Italian progressive rock band New Trolls. In 1979, La Scala along with Cuban-Venezuelan singer María Conchita Alonso in the lead vocals formed Ambar, a disco music duo. They recorded "Love Maniac", and the song "It's Time to Dance" became a hit, earning them a Gold album