Sandra Nasić was born in Göttingen, West Germany, where she grew up with her Croatian mother and her sister. After she had received her high school diploma, Nasić considered studying design, but decided to pursue a music career with the Guano Apes, which she joined in 1994. The band's career took off in 1996 after they won the "Local Heroes" competition held by VIVA, beating out over 1000 competitors with their song "Open Your Eyes". The Guano Apes debut album Proud Like a God peaked at No. 4 in Germany in 1997. Their next two albums, Don't Give Me Names (2000) and Walking on a Thin Line (2003) both reached No. 1. The Guano Apes broke up in February 2005, following touring.
Whilst still with the Guano Apes, Nasić featured on Apocalyptica's 2001 single Path Vol. 2, which reached No. 4 in Finland,and on DJ Tomekk's 2003 single Beat Of Life (along with Ice-T and Trigga Tha Gambla) which reached No. 12 in Germany.