Simon Keenlyside made his first appearance in a major operatic role in 1987 as Lescaut in Manon Lescaut. Opera magazine remarked on it being an "astonishingly mature" performance, and that he "used his warm and clear baritone with notable musicianship". At this time he realized that singing Lieder on the music club circuit was never going to be a living. His professional debut as a baritone was in 1987 (not 1988, as is usually stated) at the Hamburg Staatsoper where he sang Count Almaviva in The Marriage of Figaro.

In 1989, Keenlyside joined the roster of Scottish Opera, where he stayed until 1994, performing as, among other roles, Marcello (La bohème), Danilo (The Merry Widow), Harlequin (Ariadne auf Naxos), Guglielmo (Così fan tutte), Figaro (Barber of Seville), Billy Budd (Billy Budd), Papageno (Zauberflöte) and Belcore (L'elisir d'amore). "It was fantastic training for me, couldn’t have been better".

During this period, he made debut performances at the Royal Opera House, (1989 singing Silvio), English National Opera (Guglielmo), Welsh National Opera, San Francisco Opera, Geneva, Paris, and Sydney. In an interview with The Scotsman, he says that he learned his trade over five years in leading roles in Scotland, and he feels a "huge debt of gratitude" to the company. He sang for Glyndebourne for the first time in 1993 and made his debut at the Metropolitan Opera in New York in 1996. Keenlyside has performed at virtually all the major opera houses in the world, including the Royal Opera House at Covent Garden, Paris Opera and the Metropolitan Opera.

His recordings include several issues for Hyperion Records, including music of Benjamin Britten, Emmanuel Chabrier, Maurice Duruflé and Henry Purcell. He is also a featured singer on five volumes of the Hyperion Franz Schubert Edition and on the second volume of the Hyperion Robert Schumann Edition.

In 2004, Keenlyside sang the role of Prospero in the world premiere performances of Thomas Adès' The Tempest. He participated in the EMI Classics recording of this opera. He sang Hamlet in MET in HD live transmission on 27 March 2010. He is going to sing Posa in Don Carlo there in December 2010 (HD Live again), Roberto Alagna is to be singing Don Carlo in this performance.

Angelika Kirchschlager (born 1965, Salzburg) is an Austrian mezzo-soprano opera and lieder singer.

Kirchschlager began her musical training at the Mozarteum in Salzburg, where she studied percussion and piano. In 1984, she went to the Vienna Music Academy, where she studied with Gerhard Kahry and Walter Berry. Her first engagements were at the Wiener Kammeroper and the Graz Opera House. Kirchschlager won third prize in the International Hans Gabor Belvedere Singing Competition in 1991. Her stage debut was in Graz in 1993 as Octavian (Der Rosenkavalier). In 1993, she became a member of the Vienna State Opera, and made her debut there as Cherubino (The Marriage of Figaro).

In 2002, Kirchschlager sang the role of Sophie in the world première of Nicholas Maw's opera Sophie's Choice at the Royal Opera House in London, and the American premiere of the revised version of the opera at the Washington Opera. She is a regular guest of the annual Lieder festival Schubertiade Schwarzenberg in Vorarlberg, Austria. Her regular collaborators include Helmut Deutsch and Simon Keenlyside.

Kirchschlager resides in Vienna. She has a son, Felix, from her marriage to the baritone Hans Peter Kammerer. Kirchschlager and Kammerer are currently separated.