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
La Lodoiska a ballet of the same name choreographed by Lorenzo Panzieri, which premiered at La Fenice in January 1797, and the opera itself was revived at La Fenice in November of that year. On 4 November 1798 it had its first performance at the Teatro Real de São Carlos in Lisbon in celebration of the name day of Carlota Joaquina of Spain. Mayr then revised the opera to a two-act version which nevertheless had more musical numbers than the original three-act version. The new version premiered at La Scala on 26 December 1799. It was Mayr's first opera to be performed