Lauritz Melchior was the first of the great Wagnerian heldentenors (heroic tenors) to sing on records, and he was the first operatic tenor to sing on radio. His recorded legacy is considered a benchmark for all subsequent Siegfrieds and Tristans. One can only imagine what a legacy was lost when he and his wife fled Germany in 1939; his home there was subsequently occupied and looted by both German and Russian soldiers and a collection of unpublished recordings was used for target practice.

Melchior started singing at an early age, when a boarder in his father's house who was a voice teacher gave Melchior and the other children in the family singing lessons. He often accompanied his sister (who was blind) to the opera, and from her reactions he learned how dramatically powerful a voice can be, even without stagecraft. Like many Wagnerian and heroic tenors, he started his career as a baritone (and very briefly as a bass), first studying privately with Paul Bang, and after he turned 21, studying at the Copenhagen Royal Opera School. He made his official debut in 1913 as Silvio in I Pagliacci at the Royal Opera. He remained there for several seasons, first in comprimario roles, and later in major roles, beginning what looked like a solid career as a Verdi baritone when singing di Luna in Il Trovatore and the elder Germont in La Traviata.

A colleague heard him take an unwritten high C in Il Trovatore one evening and told the directors of the Royal Opera she heard the foundation of a heldentenor in Melchior's voice. The management agreed and made arrangements for him to restudy his voice with the tenor Wilhelm Herold. He made his debut as a tenor in 1918 as Tannhauser, again at the Copenhagen Royal Opera. However, he was still uncertain of his technique and voice. In 1919, a wealthy patron encouraged the conductor Henry Woods to audition him, and he had his London debut at the Proms in 1920. He came to the attention of another patron, Hugh Walpole, the noted author, who provided Melchior with a generous allowance to further his studies as well as support his family. His Covent Garden debut was in 1924 as Siegmund. He auditioned for Siegfried Wagner (the son of the composer) and made his Bayreuth debut in 1924 as Parsifal. He continued to take leading roles there, including the legendary 1930 Tristan und Isolde under Toscanini, who dubbed him "Tristanissimo," until shortly before World War II. His Metropolitan debut was in 1926 as Tannhauser and he sang there regularly until 1950, when one of Rudolf Bing's first actions as general manager was to decline to renew his contract.

After this dismissal, Melchior retired from the stage, though he continued to appear in films and operettas, sang on the radio (including a broadcast of the first act of Die Walküre from Copenhagen on his 70th birthday), and as part of his own touring music company., Rovi