Born in Lauterach, Bavaria, Ludwig received voice lessons in Munich from Luise Willer and Rudolf Hartmann, and also from Franziska Martienssen-Lohmann.
She appeared as Fricka, Rossweiße and Wellgunde in Der Ring des Nibelungen and as a flower maiden as well as a squire in Parsifal.
[2] At the Vienna State Opera, she gave guest performances from 1956 to 1962, as Octavian in Der Rosenkavalier and as the composer in Ariadne auf Naxos, both by Richard Strauss, and as Iocasta in Stravinsky's Oedipus Rex.
[4] Further guest performances led her to the Teatro San Carlo (1952), at La Fenice in Venice, to Amsterdam, Zurich (1955 as Clairon in Capriccio), Barcelona, Dublin, and Geneva.
Roles in Ludwig's repertoire were Dorabella in Mozart's Così fan tutte, Orfeo in Gluck's Orfeo ed Euridice, Cherubino in Mozart's Le nozze di Figaro, Ortrud in Wagner's Lohengrin, Brangäne in Tristan und Isolde, Kundry in Parsifal, Clairon in Capriccio by Richard Strauss, Baroness Grünwiesel in Henze's Der junge Lord, Eboli in Verdi's Don Carlos, the title role in Bizet's Carmen, and Nicklausse in Offenbach's Hoffmann's Erzählungen.