Ironically enough, his most famous recordings are not the grief-stricken arias of doomed characters, but light operetta arias and movie songs that, like so many of Wunderlich's recordings, capture an effervescent romance and joie de vivre rarely equaled. His voice had an immediately distinct timbre and seemingly effortless high notes, as well as a graceful, light touch that was extremely effective for operetta and song. He sang in the local synagogue choir, and was often called upon by the local theaters when a child's voice was needed, but it was not until after he had entered school that he decided to attempt a singing career. In 1924, he entered the Berlin State Academy for Music and Song, and after graduating, turned away from opera houses for stage roles, he began a career as a radio singer. In 1929, he sang Vasco da Gama in a radio broadcast of Meyerbeer's L'Africaine, and as his fame spread, performed as a concert singer worldwide, and also made a number of films, the most famous of which is Ein Leid geht um die Welt, whose title song, especially, was an instant hit. Returning to Europe before the war years, he attempted to leave too late, and finally ended up in the internment camp in Switzerland.
Fortunately, he left a wide recorded legacy, mostly operetta and song but also lieder and opera. Many of his best recordings have been compiled by EMI.