Anette Olzon was raised in a musical family and has been singing since childhood. She began playing the oboe at age 8. She toured with her mother's band and sung with them on some occasions. Later, she started to take part in various talent shows and received laudable recognition. The first band she joined, when she was 17, (Take Cover) was a cover band. However, it was short-lived as she took part in several bands and projects. At 21, she played the leading role in the rock opera/musical "Gränsland" in Helsingborg. After that she got in to the Balettakademien in Gothenburg. She sang in choirs, did studio work for various projects and occasionally performed as a wedding singer. Anette Olzon also sang a duet with Michael Bormann (ex-Jaded Heartsinger) on his album "Conspiracy".

Olzon then joined Alyson Avenue, and later replaced the male vocalist. The band received huge feedback for a demo they sent out in 1999, and Alyson Avenue was soon able to contact various labels. Main composer and keyboardist Niclas Olsson gathered the band, recording a four track demo which resulted in a record deal with AOR Heaven.

In November 2000, debut album Presence of Mind was released with rave reviews. The next album Omega was released in 2003. The band retired in 2006. Olzon joined Nightwishin 2007, and the other band members continued with a male lead vocalist and a new name, Sapphire.

Olzon officially joined Nightwishas their new lead singer in early 2007, chosen from about 2,000 applicants of which 10 made it to prove their place in front of the band. The song on her demo tape was the 2002 single "Ever Dream". She replaced the previous singer Tarja Turunen who was fired in an open letter in the fall of 2005. Her identity was kept secret until May 24, 2007. The internet single Eva was released the day after she was announced as a singer. Although critics are divided over the replacement of Tarja Turunenby Anette Olzon, the two singers present very different types of vocals, with Turunen being an operatic, classically trained singer (soprano), and Olzon taking an approach akin to rock. It has been confirmed that Olzon will sing a duet with Lauri Ylonen, which will feature on the new album Black Roses.