 George Grossmith was born in Haverstock Hill, London, the eldest son of the writer and Gilbert and Sullivan star George Grossmith, and his mother was Emmeline Rosa, née Noyce.His grandfather was also named "George Grossmith", and even though he was the third George Grossmith, he was credited on stage as "George Grossmith Jnr".His brother was the actor Lawrence Grossmith.