Klaas de Vries was born on 15 July 1944 in Terneuzen, in the province of Zeeland in the Netherlands. From 1965 to 1972 he studied piano, theory and composition on the conservatory of Rotterdam. He continued studying composition from 1972 at the conservatory of The Hague with the Dutch composer , winning the composition prize there in 1974. After winning this prize de Vries studied with the Croatian composer Milko Kelemen in Stuttgart, Germany. De Vries won the Matthijs Vermeulen Award twice: in 1984 for his work "discantus" (1982) and in 1998 for his opera "A King, Riding" and the "Interludium" for string orchestra (1996).