Bernadett Wiedemann was born in Mosonmagyaróvár. She entered the vocal faculty of the Győr Conservatoire and later she graduated from the Music Academy as a student of Zsolt Bende and Zsuzsanna Eőry. Since 1993  she has been a member of the Hungarian State Opera House. In 1989, she came first in both the lieder and oratorio categories at the Karlovy Vary competition and in 1997 placed third at the Rome Competition.

She has sung the alto parts of numerous oratorios and masses both in Hungary and abroad and performed as a guest in virtually all the countries of Europe as well as Japan and Brazil. She has worked with such artists as László Polgár, Yevgeni Nesterenko, José Carreras as well as conductors such as Yuri Simonov, Pier Giorgio Morandi, Rico Saccani and Ken-Ichiro Kobayashi. She has been awarded the Mihály Székely commemorative plaque and the Juventus Prize in recognition of her achievements.