Born into an artists' family, he studied as an actor and dancer, but also sang with his sister, Maria. By the 1960s, Duval was also composing music, both orchestral and pop, and his first soundtrack, for an episode of the German serial Tatort, was broadcast in 1977. From his 1979 first album, Die Schönsten Melodien Aus Derrick und der Alte, the song "Todesengel" became a moderate hit.
During the 1980s, Duval released several soundtracks, as well as proper artist albums (with occasional lyrical help from his wife, Kalina Maloyer). He was in the German charts several times, with "Ways" (1983), "Lovers Will Survive" (1986), and "When You Were Mine" (1987).