After completing his studies with Helmut Hucke at the Cologne Musikhochschule, Hans-Peter Westermann in 1976 became a member of the Orchestra of the Deutsche Oper Berlin, and later of the WDR Symphony Orchestra Cologne.
From 1982 onwards he opted for a freelance career and appeared with many leading ensembles, including Concentus Musicus Wien, Neue Düsseldorfer Hofmusik, Musica Antiqua Köln, Anima Eterna and Sonatori della Gioiosa Marca.
Between 1988 and 1992 he was visiting professor of oboe at the Musikhochschule in Vienna and up to 2009 he teached at the Musikhochschule in Frankfurt.
Since 1989 Hans-Peter Westermann has also devoted himself to instrument making.