Having Germanised his name to "Friedrich Dalberg", he made his debut in 1931 as Monterone in Rigoletto at the Leipzig Opera where he also sang Sarastro in The Magic Flute, Osmin in Die Entführung aus dem Serail, Henry the Fowler in Lohengrin and several other Wagner roles.
Dalberg sang at the Bayreuth Festival (1942–44 and 1951), taking the parts of Fafner in Das Rheingold and Hagen in Götterdämmerung.
There he created roles in two Benjamin Britten operas, John Claggart in Billy Budd (1951), and Sir Walter Raleigh in Gloriana (1953).
He was in the British stage première of Alban Berg's Wozzeck (1952) as well as the debut casts of William Walton's Troilus and Cressida (1954) and Michael Tippett's The Midsummer Marriage (1955).
In addition, his repertoire included King Mark in Tristan und Isolde, Hunding in Die Walküre, Caspar in Der Freischütz, Don Pizarro in Fidelio, Sparafucile in Rigoletto and Bartolo in The Marriage of Figaro.