Even before completing his studies, Fancourt was building a concert career in London, the British provinces and the European continent. "The Times" said of an Aeolian Hall recital in 1912, "Mr. Fancourt has some noble notes in his voice, except when he forces it occasionally ... Schubert's "Tod und das Mädchen" was remarkably well characterized; it was quite his best and he made it into a thing of great beauty." In World War I, Fancourt volunteered for military service and was commissioned in the London Regiment as a lieutenant. In 1917, while still serving in the army, Fancourt married a beautiful Welsh singer, Eleanor Evans, at St Mark's Church, Hamilton Terrace, London. She had been a fellow student at the Royal Academy. After returning to civilian life in 1919, Fancourt sang in a single performance of "Prince Igor" in Sir Thomas Beecham's opera season at Covent Garden as Prince Galitsky under the baton of Albert Coates. This was his only professional appearance in a grand opera, and his only paid acting experience up to that point. In the same year, he appeared as a soloist at the Henry Wood Promenade Concerts and in oratorio elsewhere in London.