After finishing his opera studies, Khan joined the Norwegian progressive metal band Conception, after its previous lead singer quit in 1991.

In 1997, Khan was invited to join Kamelot by guitarist and founder Thomas Youngblood, after the band's previous vocalist was fired.

Khan performed lead vocals on the subsequent releases Siége Perilous (1998), The Fourth Legacy (1999), Karma (2001), Epica (2003), The Black Halo (2005), Ghost Opera (2007), and Poetry for the Poisoned (2010).

[5] The tour eventually went on with Fabio Lione filling in on vocals, while his permanent replacement, Tommy Karevik, joined Kamelot the following year.

[8] In a 2018 interview with Italian magazine Loud and Proud, Khan elaborated on his final years with Kamelot, stating that he had become gradually more and more burned out due to overworking himself, suffering from insomnia and depression.

[10] On 1 April 2018, Khan released a song on YouTube called "For All", leading many fans to speculate in an upcoming return to music.