Ms. Gayer has participated in several world premieres, including André Previn's A Streetcar Named Desire with San Francisco Opera and later with New Orleans Opera, Mrs. Bass in Tobias Picker's Emmeline with Santa Fe Opera (also on Albany Records), and Rita the Rat in Mr. Picker's Fantastic Mr. Fox with Los Angeles Opera. With New York City Opera, Josepha Gayer has sung Katisha in The Mikado, Marcellina in Le nozze di Figaro, Emma Jones in Street Scene, Mrs. Bass in Emmeline, and Mama in the New York premiere of Oliver Knussen's Where the Wild Things Are.

Josepha Gayer's Lyric Opera of Chicago debut was as The Mother in The Consul, a role she has also sung with L'Opéra de Monte-Carlo and Portland Opera. She returned to Lyric Opera of Chicago to sing Berta in Il barbiere di Siviglia, a role she has also sung with Madison Opera. Ms. Gayer made her Santa Fe Opera debut as Mother Goose in The Rake's Progress and returned to the company for Arabella and Die Zauberflöte, as well as Buttercup in Gilbert & Sullivan's H.M.S. Pinafore. She made her debut with Opera Theatre of Saint Louis as Madame de la Haltière in Massenet's Cendrillon.

Ms. Gayer has sung Mrs. McLean in Susannah with Houston Grand Opera and Washington Opera, Augusta Tabor in The Ballad of Baby Doe with Boston Lyric Opera, and the role of Mama McCourt in the same opera with San Francisco Opera. She has sung the role of Katisha in The Mikado with Vancouver Opera, Nastassja in the American premiere of Hans Krasa's Verlobung in Traum with the Washington Opera, and Mother Marie in Dialogues of the Carmelites with Tulsa Opera. Other past engagements include the roles of Shonagon and Kokiden in The Tale of Genji with the Opera Theatre of Saint Louis, Marquise in La Fille du régiment with Opera Columbus and Cleveland Opera, and Mamma Lucia in Cavalleria rusticana and Cecilia March in Little Women with Glimmerglass Opera.

Josepha Gayer made her Carnegie Hall debut with the Manhattan Philharmonic in Menotti's O Pulchritudo, and has received widespread acclaim for concert appearances in Mahler's Symphony No. 3, the Verdi Requiem, Beethoven's Symphony No. 9, and Vaughan Williams's Hodie in venues across the country, including the Cleveland Orchestra, Fort Worth Symphony, San Antonio Symphony, Akron Symphony and the Orchestra Society of Philadelphia, among others.