In 1962, Hess wrote and recorded "Speedy Gonzales", (as David Dante)[1][3] which became a #6 single for Pat Boone in the U.S. and a #2 in the UK, selling more than 8 million copies worldwide.

There he linked with Western classical composer John Corigliano, and together they wrote the Grammy Award-winning rock opera The Naked Carmen, which became a big hit of the Berlin Ballet Week in 1970.

His work with Mercury included And the Children Toll the Passing of the Day, a 1969 album he wrote for Irish actor Malachy McCourt.

In 1972, his career split into several new directions with his starring role in the Wes Craven horror classic The Last House on the Left, for which he also composed the soundtrack.

A subsequent job offer from PolyGram's German affiliate gave Hess the opportunity to move to Munich, Germany, and a multilingual career in film dubbing from 1972 to 1976 which in turn led him to writing the English language shooting scripts for German directors such as Rainer Werner Fassbinder, Reinhard Hauff, and Peter Schamoni.

He also appeared in two horror films directed by Ruggero Deodato: La Casa sperduta nel parco (1980) and Camping del terrore (1987).

From 1993 to 1995, he produced Niki de Saint Phalle: Wer ist das Monster - du oder ich?

This was intended as a posthumous tribute and the liner notes on the release include extensive writings by Hess' family, colleagues and friends.

[6][7] On October 7, 2011, Hess suffered a fatal heart attack near his home in Tiburon, California, and died on his way to his car after dinner with friends.