Fischer took Albani's advice and began taking voice lessons with Hutchinson. While still a student at the Royal College of Music, she made her London debut in 1922 at the Old Vic as the Countess in Mozart's Marriage of Figaro. That same year, she sang the role of Micaëla in Carmen at the Old Vic, and debuted at Covent Garden in the role of Pamina in Mozart's The Magic Flute.
On January 8, 1923, Fischer sang the role of Pamina again, as a part of the British Broadcasting Company's (BBC's) first radio broadcast of opera from Covent Garden -- an historic event in opera performance. Around this time, she made several more recordings in 1923 with HMV (London), which featured Elizabethan love songs by Dowland, Bartlet and Campion.
During her third year of studies at the RCM, Fischer joined the newly formed British National Opera Company and appeared as Eva in Wagner's Die Meistersinger. After she completed her final year at the RCM, she travelled to Rome and continued her studies for another year with Vincenzo Lombardi, who also had taught the legendary Enrico Caruso and Canadian tenor Edward Johnson.
Fischer returned to Covent Garden in 1925 and performed the role of Olga in Giordano's Fedora. She also gave a number of recitals in London at venues such as Wigmore Hall, Albert Hall and Queen's Hall. On May 28, 1925, Fischer and a number of internationally acclaimed artists such as composer/conductor Sir Edward Elgar and Australian diva Nellie Melba, presented a benefit gala at Covent Garden for Emma Albani, who was experiencing severe financial difficulties. The proceeds from this gala, along with other funds that were raised, allowed the aging singer to live in comfort for the remainder of her life.
A few months later, in November, Sarah Fischer's career took a significant turn when she joined the prestigious Opéra-Comique in Paris. At the time, Fischer had been vacationing in Paris, and through a friend was invited to hear an audition that M. Mason of the Opéra-Comique was conducting. Sitting in the audience, Fischer listened as a singer auditioned and M. Mason accompanied. When the auditioning singer lost his place in the music, Fischer sang a few notes to help him out. M. Mason liked what he heard and asked her to audition for the Opéra-Comique. After her audition, M. Mason invited her to join his company and Fischer accepted.
She debuted at the Opéra-Comique on November 20, 1925, performing for the first time what would become one of her most celebrated roles: Mélisande from Debussy's Pelleas et Mélisande. Fischer learned this challenging role in only ten days, and it became one of her favourites to sing: "For the voice I preferred Mozartian roles; for acting, Carmen;" she explained in an interview, "for poetry, Mélisande every time. When I die I want to be buried in her dress with the score of Pelleas and Mélisande for my pillow. It is always at my bedside" (Sarah Fischer Archives, A1 9901-0002).
As a member of the Opéra-Comique for 15 years, Fischer sang 30 leading operatic roles including Charlotte in Werther, the title role in Mignon, and Cherubino in The Marriage of Figaro. While in Paris, she also had other prestigious engagements. In 1927, she was engaged by director Bruno Walter to sing in a series of Mozart operas at the International Mozart Festival at the Odéon Theatre. She appeared in the roles of Pamina from The Magic Flute and Dorabella from Cosi Fan Tutte.
Her operatic career also took her to Algiers, Brussels (1926), and the Opera in Monte Carlo (1927) where she sang the title role in Thomas's Mignon. In 1936, she sang the principal soprano role in the world premiere of Albert Coates' opera The Pickwick Papers.
In addition to performances on the operatic stage, Fischer was a celebrated recitalist, and gave numerous concerts in London, Paris, Rome, Vienna and Berlin. She was admired for her interpretations of music by French composers Claude Debussy, Maurice Ravel, Francis Poulenc, Albert Roussel, Darius Milhaud and Jacques Ibert, and often performed their music with the composers accompanying her at the piano.
Her recitals met with great critical success, evidenced in the following review after a recital at Wigmore Hall in London:
From grave to gay; from the delightful whimsicality of the Miller's song in "Le Roy d'Yvetot" by Jaques [sic] Ibert to the flowing periods of a Beaudelaire poem taken from "Les Fleurs du Mal," she ranged with astonishing mastery, perfect diction and profound insight. Two poems by Charles Vildrac set to music by Jaques [sic] Ibert…. were given their first public performance in London. … A charming thing by Poulenc, "Deux Airs Chantés," not previously performed here, was equally well received (Cummings, Evening Citizen's London News Bureau, [no date]).
During her career, Fischer toured Canada on several occasions. She made her first trip to Canada in 1927, where she gave recitals at Windsor Hall, the Montreal Ladies Morning Musical Club, and at Rideau Hall for the opening of the Parliament State Dinner.
In December 1929 Sarah Fischer married English pianist Herbert Carrick, and he joined his wife on her second trip to Canada as her accompanist. They performed in Montréal, Québec, Toronto and Ottawa, and then in New York, Washington and at the Mana-Zucca music club in Miami.
An English writer reported on Fischer's success in Miami, and the effect her performance had on one wealthy patron:
The voice of Mrs. Herbert Carrick, wife of the noted pianist, whose Worcester home is at 20 Hancock street, so charmed Mrs. Bracket Bishop of Chicago, during a recital at the Nona-zucca [sic] club, Miami, that it won for her a 500 year old jewelled head-dress of gold in lotus leaf design, set with rubies and turkuoise [sic] ….Mrs. Bishop is a connoisseur of rare and precious stones ("Vocal ability…", 1930).
Before the concert, Fischer and her husband had been introduced to Bishop and shown her collection of jewels. Fischer's husband described what happened next:
We wanted that head-dress the moment we saw it…but it was too valuable for us to consider buying…. Then came the night of the concert, a special Spanish program. Mrs. Carrick was never in better voice. Among her admirers in the audience was Mrs. Bishop…. The next morning at 9 o'clock Mrs. Carrick received a phone call to meet Mrs. Bishop. And then it was that she received the greatest surprise of her career. Mrs. Bishop, entranced by my wife's singing, presented her with the head-dress ("Vocal ability…", 1930).
Sarah Fischer wore the head-dress in May 1930 when she created three roles at the Liege Opera House in Belgium.
In July 1934, Sarah Fischer ventured into the world of television, and made history with the BBC when she appeared in the role of Carmen in the world's premiere performance of an opera on television. A writer from the Daily Telegraph described the event as follows:
The BBC will to-day make its first attempt to broadcast a full-size opera -- Carmen -- in the space of half-an-hour. This feat of compression … will occur in the television period from 11 to 11:30 this morning, when a cast of three -- Sarah Fischer, the Canadian operatic soprano, Heddle Nash, the concert and stage tenor, and Elsa Brunelleschi, the Spanish dancer -- will give a "colourable representation" of the complete opera.
About this occasion, Sarah Fischer recalled,
….we were then only able to synchronize two or at the utmost three artists on the screen at the same time…faces were not clearly defined as there were no "close-ups"…the make up was green for the lips, red when black was needed, and yellow for white….a chosen artist would not only have to be an accomplished musician and most reliable, as the conductor was not visible, she would also have to have a sound stage technique for the same reason, as the stage setting was no higher or broader than a large mantle shelf. This special schooling required knowledge of how high to raise the arms, or where to place a limb, for the height of the knee had to fit in with the position of the tenor playing Don Jose when kneeling at Carmen's feet with his head in her lap at the end of his aria "The Flower Song" (Sarah Fisher Archives, MG30 D207, vol. 1).
By the beginning of the Second World War, Fischer was at the peak of her career. She spoke four languages fluently, had performed in the major opera houses and concert halls in Europe, and her repertoire consisted of 22 leading operatic roles. Due to the war and the blackout, however, large music organizations in London such as Covent Garden had closed down. Undeterred, Sarah Fischer tried her hand at arts administration by organizing a new concert series at Wigmore Hall that she named the "Sarah Fischer 12 O'Clock Concert Series". Featuring Fischer and other London-based Canadian artists, these noon-hour concerts provided music for London commuters from a variety of backgrounds. The British press described Sarah Fischer one of the people who kept music alive in London during the Blitz.