Aafje Heynis was born on May 2, 1924 in Krommenie, Noord-Holland, Netherlands. She was married to Henk Dolk. She died on December 16, 2015 in Huizen, Noord-Holland, Netherlands.
At the age of four she sang in a children's choir as well as with her father at the harmonium.
Aafje Heynis showed a particular preference for Gustav Mahler, one consequence of which was a legendary recording of his Symphony No. 2 with the Royal Concertgebouw Orchestra conducted by Bernard Haitink.
With her performance in Johannes Brahms' Alto Rhapsody with the Royal Concertgebouw Orchestra under the direction of Eduard van Beinum, she attracted wide attention.
On the advice of Jan Mienes, the conductor of the choral society in her native town, she auditioned for teacher Jo Immink in Amsterdam with an arrangement of the "Pilgrims' Chorus" from Richard Wagner's Tannhäuser.
From 1946 to 1949 her singing teacher was Aaltje Noordewier-Reddingius and she was also advised by Laurens Bogtman, the great oratorio singer.