He remained with the Concertgebouw Orchestra for seven years, after which he focused on chamber music and a solo career.
Among his students have been Christopher Bouwman, Peter Bree, Frank van Koten, Wolfgang Lange, and Bart Schneemann.
As a soloist, De Vries has toured Europe, Japan, Australia, and North and South America, with a repertory of baroque, classical, romantic and contemporary music.
He has made many recordings, one of which (of the oboe sonatas of Schumann, Bartók, Ben Haim, Poulenc and Shinohara with pianist Rudolf Jansen) won an Edison Award in 1973.
Most of these pieces employ unorthodox techniques for oboe like multiphonics, fluttertonguing, and glissandi, as if to emphasize De Vries' wide range from baroque to postmodern music.