Donald Adams was born in Bristol and educated at the Bristol Cathedral School, where he sang as a chorister in the cathedral and played Thomas Becket in "Murder in the Cathedral" at the age of sixteen. While still at school, he made his first professional appearance as an actor in 1944 with the BBC Repertory Company. He studied with an Italian singing teacher in London, Rodolfo Melle (who had sung at La Scala with the tenor Aureliano Pertile), who taught Adams to sustain the vowels of a word before reaching the consonants. This, Adams said, gave the voice "a nice line", and he continued to practise Melle's lessons until the end of his life.