In 1909 he was given supporting roles at the Royal Opera, before being given the part of Méru in Meyerbeer's Les Huguenots, singing with Luisa Tetrazzini.
Early in 1913 he participated in an unsuccessful production of Raymond Roze's Joan of Arc, but later that year he was fortunate in playing leading roles more to his liking in Wagner's Tristan und Isolde, Lohengrin and Bizet's Carmen.
In 1914 the English composer Sir Edward Elgar attended the Festival, expecting to hear Tristan, but instead of that the curtain rose on Meistersinger in which Mott by chance took August Kiess's part of Kothner.
In 1916 Mott played the part of the Angel of the Agony in Gerontius, alongside Clara Butt and Gervase Elwes, with the composer conducting.
Lance-Corporal Charles James Mott was buried in grave 2, plot 11, row C of Bagneux British Cemetery, south of Gezaincourt (Somme), France.