Willis-Sørensen performs a wide variety of repertoire ranging from Mozart to Wagner. She is most well-known for her interpretation of Donna Anna , Marschallin , and the title role in Rusalka. Roles included in her repertoire include: Elettra, Licenza, Vitellia, Countess Almaviva , Fiordiligi , Hélène, Eva, Elsa von Brabant, Gutrune, Rosalinda , Agathe, Hanna Glawari in The Merry Widow, Diemut , Leonore, Ariadne , Mimì, Leonora , Masha , Governess , and Marguerite . She made her professional debut as the High Priestess at the Utah Opera Festival in 2008, and was accepted into the Houston Grand Opera Studio the following season, where she made several debuts and covered multiple roles. In the 2009/10 season in the program, Willis-Sørensen made her mainstage debut with the company as Masha in Pique Dame and covered Elsa in Lohengrin and the Governess in The Turn of the Screw. In the 2010/11 season, she sang the role of Kate Pinkerton in Madama Butterfly and Fiordiligi in Così fan tutte as a part of the Houston Grand Opera Studio performances. She also covered Ellen Orford in Peter Grimes, Countess Almaviva in The Marriage of Figaro, and the title role in Ariadne auf Naxos. Later that season, she made her Santa Fe Opera debut as the First Lady in Mozart's The Magic Flute and performed excerpts from Arabella as a member of their Apprentice Program. In the 2011/12 season, Willis-Sørensen made her Royal Opera House, Covent Garden, debut as Countess Almaviva in The Marriage of Figaro under music directorAntonio Pappano. She sang with the Los Angeles Philharmonic in Beethoven's Symphony No. 9 under Leonard Slatkinat the Hollywood Bowl, and appeared at the Opera Theatre of Saint Louis as Fiordiligi in Così fan tutte and Gotham Chamber Opera as Licenza in Christopher Alden's production of Mozart's rarely heard Il sogno di Scipione to celebrate their 10th anniversary. She returned to Covent Garden as Gutrune in Götterdämmerung, again under Antonio Pappano and Houston Grand Opera as Donna Anna in Don Giovanni. She was a member of the Semperoper Dresden ensemble from 2012 until 2015, where she continued to add to her repertoire, most notably, the title role in The Merry Widow, Fiordiligi in Così fan tutte, Vitellia in La clemenza di Tito, Elettra in Idomeneo, Diemut in Feuersnot, Rosalinde in Die Fledermaus, and MimÌ in La bohème. As a freelance artist, her career continued to develop to include debuts in leading roles at The San Francisco Opera, the Bayerische Staatsoper, the Lyric Opera of Chicago, the Glyndebourne Festival, the Deutsche Oper Berlin, Opernhaus Zurich, the Metropolitan Opera, the Wiener Staatsoper, and the Accademia di Santa Cecilia. Highlights from her 2018/19 season included her role debut as Leonora in Il Trovatore at the Teatro Regio di Torino, Rosalinde in Die Fledermaus in a televised performance also featuring Jonas Kaufmann, Hélène in Les Vêpres Siciliennes at the Bayerische Staatsoper, Donna Anna in Mozart's Don Giovanni at the Metropolitan Opera, and her role debut in the title role in Rusalka at the San Francisco Opera. In the 2019/20 season, her plans include her role debut as Marguerite in Faust in Tokyo as part of the Royal Opera House on tour,, Marschallin in Der Rosenkavalier at the Semperoper Dresden, Donna Anna in Don Giovanni at the Lyric Opera of Chicago, Bavarian State Opera and Opéra national de Bordeaux, and a role debut as Valentine in Les Huguenots at Grand Théâtre de Genève. She was to have made her role debut as Alcina at the Semperoper Dresden, and sing Contessa Almaviva in The Marriage of Figaro at the Grand Théâtre de Bordeaux, but these engagements were cancelled due the Covid-19 outbreak.
