While working as a mailman in New York City in 1961, Clark wrote songs, and discovered singer James Ray in a small nightclub.

With Arthur Resnick, Clark co-wrote "Good Lovin'", recorded by The Olympics in 1965 and then remade as a #1 hit by the Young Rascals the following year.

[6][7] Clark was nominated for the Grammy Award for Best R&B Song for his lead contribution in writing the 1972 Top Five hit "Everybody Plays the Fool" by the Main Ingredient.

Beyond pop hits, Clark wrote several songs for the early 1970s Harlem Globetrotters cartoon series.

Besides being heard on oldies radio, Clark's material has also found its way to the Broadway theatre, making reference to André DeShields' Haarlem Nocturne (1984) and Marion J. Caffey's Street Corner Symphony (1997).