Deciding to give up a legal career and try his hand on the stage,[3] on 16 May 1870 Grain joined what was known as the German Reed Entertainments, at the Gallery of Illustration, appearing in a sketch of his own called The School-Feast.

[4] At the same time, Grain entertained privately, performing his comic musical sketches at the piano for fashionable parties and other venues.

[5] Over twenty-five years, Grain wrote between fifty and sixty entertainments for the company, consisting of social sketches and songs with piano accompaniment.

[1] W. S. Gilbert disagreed, asking him to perform in his absurdist comedy with the German Reeds, Happy Arcadia, as "the handsomest man in the world", because of Grain's comical appearance.

Grain was a great friend and rival of Gilbert and Sullivan performer and fellow sketch-artist, George Grossmith.