Grosch was born in Wuppertal, North Rhine-Westphalia to a German-Australian father and Korean mother.

He gained his first professional stage experience when he started singing at weddings and other ceremonies, while simultaneously performing with his own band.

At that time he took leave from his job to participate in the third season of Deutschland sucht den SuperStar (where he also became romantically involved with co-competitor Vanessa Jean Dedmon).

Because of his strong, husky voice and a few similarities to British singer Seal, Grosch became an early favourite with the judges and the audience, who enabled him to sing against competitor Tobias Regner during the final show.

In early March 2007, Grosch admitted to Bild, the biggest German daily tabloid, that SonyBMG would not continue their existing record contract with him and thus was being dropped.