At the age of 17, he entered the Brussels Royal Conservatory and studied with Frederic Anspach. A year later, he graduated with diplomas and first prizes in voice and opera performance. He made his opera début as the music teacher Don Basilio in Gioacchino Rossini’s "Il Barbiere di Siviglia" at the Paris Opera in 1961, and remained in the company until 1965, when he sang his first major role, Escamillo from Bizet's "Carmen". He then sang for two seasons at Geneva, La Scala, Covent Garden, and in Paris. At Geneva, Van Dam sang in the première of Milhaud's "La mère coupable" in 1966. Lorin Maazel heard van Dam and invited him to record Ravel’s "L’heure espagnole" with him for Deutsche Grammophon. In 1967, Maazel asked him to join the Deutsche Oper in Berlin.