In recent years she has been active as a stage director for opera productions in Germany, France and America, and worked as a voice teacher and master class instructor.
While a student she began her career performing as an ensemble member in the original Broadway production of Rodgers and Hammerstein's The Sound of Music in 1959-1960, including the opening night.
Some of the more than 120 leading roles she has performed on stage include: Brünnhilde in Wagner's Götterdämmerung, Carlotta in Schreker's Die Gezeichneten, Chrysothemis in Richard Strauss's Elektra, the Countess in Tchaikovsky's The Queen of Spades, Donna Elvira in Mozart's Don Giovanni, Elvira in Rossini's L'italiana in Algeri, Giorgetta in Puccini's Il tabarro, Lady Macbeth in Verdi's Macbeth, Leonore in Beethoven's Fidelio, Madeleine in Adam's Le postillon de Lonjumeau, Marguerite in Gounod's Faust, Marie in Zimmermann's Die Soldaten, Marie in Donizetti's La fille du régiment, the Marschallin in Strauss's Der Rosenkavalier, Micaela in Bizet's Carmen, Melisande in Debussy's Pelléas et Mélisande, Minnie in Puccini's La fanciulla del West, both Mimì and Musetta in Puccini's La bohème, Nedda in Leoncavallo's Pagliacci, Norina in Donizetti's Don Pasquale, Giulietta in Offenbach's The Tales of Hoffmann, Rosina in Rossini's The Barber of Seville, Sieglinde in Die Walküre, Violetta in Verdi's La traviata, the Woman in Poulenc's La voix humaine, Zdenka in Strauss's Arabella, and the title roles in Aida, L'incoronazione di Poppea, The Cunning Little Vixen, Jenůfa, Lulu, Káťa Kabanová, Madama Butterfly, Salome, and Tosca.
[4] She performed the part of the Duchess of Parma in Ferruccio Busoni's Doktor Faust at the Oper Frankfurt in 1980, staged by Hans Neuenfels, with Günther Reich in the title role and William Cochran as Mephistopheles.
[9] In 1980 Card premiered Wilhelm Killmayer's Französisches Liederbuch at the Schwetzingen Festival with baritone Philippe Huttenlocher and the Südwestdeutsches Kammerorchester, conducted by Paul Angerer.