Born in the southern Hungarian town of Kiskunhalas, she spent her youth as an athlete training for the heptathlon. Due to an accident, however, she was forced to switch career paths. Because of her good singing skills she chose to be a singer. At first, she sang at family gatherings, weddings, and formal celebrations. On one such occasion, a singing-master heard her and almost immediately began to teach the 16-year-old Erika. Soon she went on to study music at the Franz Liszt Academy of Music in Szeged as well as in Milan and New York. She became a soloist at the Hungarian State Opera in 1990. Her signature role is the Queen of the Night from Mozart's The Magic Flute. She sang also at the Royal Opera House in London, at the Vienna State Opera, at the Metropolitan Opera in New York and many more famous opera houses. Already in 1991 she was engaged at the Hungarian State Opera as a soloist. She is best known as an interpreter of the role of the Queen of the Night in Mozart's The Magic Flute. In 2004, she debuted at the Metropolitan Opera in this role.
Miklósa was Hungarian Junior Champion in the high jump. However, an accident hindered any further career.