He is best remembered as a music director of the D'Oyly Carte Opera Company and for his association with Sadler's Wells Theatre. One of his ballets, The Haunted Ballroom (1934), became popular and was revived several times, and the new overture that he prepared for Gilbert and Sullivan's Ruddigore in 1919 became the standard version.
By 1913 Toye was conducting in major London theatres – for Maurice Maeterlinck's Blue Bird at the Haymarket Theatre, Marie Brema's opera season at the Savoy Theatre, and for the première of George Bernard Shaw's Androcles and the Lion. In 1914, he was entrusted by Ralph Vaughan Williams with conducting the première of his London Symphony at the Queen's Hall. When the manuscript was lost (having been sent to Fritz Busch in Germany just before the outbreak of World War I) Toye, together with George Butterworth and the critic Edward J. Dent, helped Vaughan Williams reconstruct the work. Also in 1914, Toye introduced Butterworth's rhapsodies A Shropshire Lad and The Banks of Green Willow to London audiences. The night before the première of The Planets, Toye dined with the composer, Gustav Holst, and Adrian Boult. According to Boult, Toye took exception to one bar in "Neptune", where the brass play chords of E minor and G# minor together: "I'm sorry, Gustav, but I can’t help thinking that’s going to sound frightful." Holst agreed, and said it had made him shudder when he wrote it down, but he insisted that it must be that way: "What are you to do when they come like that?
Toye joined the Army in 1914, first as a private in the Duke of Cornwall's Light Infantry, and later in the Royal Flying Corps, in which he served in France as a photographic specialist. He retired with the rank of major. For a time after the war he was a member of the insurers Lloyd's of London, where he organised many amateur musical activities and founded the Lloyd's Choir. He was engaged as assistant conductor of the Beecham Opera Company and also conducted concerts for the Royal Philharmonic Society in 1918 and 1919.
Rupert D'Oyly Carte, a fellow Wykehamist, appointed Toye as music director for three D'Oyly Carte Opera Company seasons at the Prince's Theatre in London: 1919-20, 1921-22, and 1924. In his first season there, Toye arranged a new, more dramatic, overture for Gilbert and Sullivan's Ruddigore, removing themes that had been cut from the opera and making other cuts throughout the score. Thereafter, his overture was always used by the D'Oyly Carte Opera Company, even when some cut numbers were restored in the 1970s, and it became the standard performance version. He also arranged a new overture for The Pirates of Penzance, but that did not remain in use. In 1927, Toye was joint musical director of a benefit performance for the old D'Oyly Carte leading man, Courtice Pounds, in which Toye was joined by stars from many branches of theatre, including Seymour Hicks, Evelyn Laye, Walter Passmore, Gertrude Lawrence and Derek Oldham.
From 1934 to 1936, Toye became Managing Director of the Royal Opera House, Covent Garden, working alongside the Artistic Director, Sir Thomas Beecham. Despite early successes, Toye and Beecham eventually fell out over Toye's insistence on bringing in a popular film star, Grace Moore, to sing Mimi in La bohème. The production was a box-office success, but an artistic failure. Beecham manoeuvred Toye out of the managing directorship in what Sir Adrian Boult described as an 'absolutely beastly' manner. Toye obtained the film rights to the Gilbert and Sullivan operas. In 1938, he adapted, produced, and conducted The Mikado, starring Martyn Green, but the onset of war prevented further screen adaptations. Toye composed and arranged the music for two other British films of the 1930s: Men Are Not Gods and Rembrandt, both for Alexander Korda in 1936.
In 1940, Toye joined the staff of the BBC, in the American Liaison and Censorship Department. Toye was twice married, first in 1915 to the actress Doris Lytton, and later to Dorothy Fleitman, with whom he had one son. Toye's elder brother, Francis, was a well-known critic and Verdi scholar. His niece, Jennifer Toye, was a D'Oyly Carte soprano in the 1950s and 1960s.
Toye died in London at the age of 53.
Toye made very few gramophone records. For HMV in 1928, he conducted the London Symphony Orchestra in recordings of Delius's Brigg Fair, On Hearing the First Cuckoo in Spring, and In a Summer Garden. The composer wrote, "All three... are excellent and I shall be glad to have them sold as authorised by me.
Toye's overture to Ruddigore has been recorded numerous times, conducted by Harry Norris, Isidore Godfrey, and Sir Malcolm Sargent (who each recorded the complete opera) and Sir Charles Mackerras, among others. Norris, Godfrey and Sargent all observe some or all of Toye's cuts and other minor alterations in the score. Toye's only recording conducting a Gilbert and Sullivan work is the 1938 film of The Mikado referred to above. Of Toye’s original music, the waltz from The Haunted Ballroom has been recorded several times, including one in the 1990s by Marco Polo. A complete recording of the ballet was made in 2001 by the Royal Ballet Sinfonia.