Nikolett Hajzer started her music studies as a member of the Hungarian State Opera Children's Chorus under the tutelage of Gyöngyvér Gupcsó and continued them at Budapest's Városmajor High School under Zsuzsanna Gráf. She obtained her degree in choral conducting from Eötvös Loránd University in Budapest after studying with Lenke Igó. A member of the Magnificat Choir between 1996 and 2016, she also regularly appeared in competitions and major Hungarian and international concert halls as a member of the Angelica Girls' Choir between 1998 and 2010. In 2010, she earned a degree in art therapy and music therapy from the University of Pécs. She taught from 2006 to 2008 at Városmajor High School, and later on, between 2009 and 2013, at the Ferenc Erkel Primary School, the school where the Hungarian State Opera Children's Chorus is based. She is currently employed as a teacher of voice and music at the Alternative Secondary School of Economics. She joined the Hungarian State Opera Children's Chorus as a répétiteur in 2012, and was appointed its head in August 2016. She received the Bronze Cross of Merit in 2023.
