Valli was educated in London and Paris. As a twelve-year-old, she made her first stage appearance in Gentle Ivy (1894) at Terry’s Theatre in London. She demonstrated her theatrical skill in Berlin in 1895 with a successful run in the musical comedy Morocco Bound. She returned to London’s Drury Lane Theatre, performing the role of the dancing doll in a pantomime version of Cinderella the following Christmas.  A strikingly beautiful woman, Valli played mostly in England thereafter, appearing in The Queen of Hearts, Purple Road and The Duke’s Motto, among other pieces. She toured the United States a number of times. Her first American tour was in the operetta Veronique in 1905, where she played the part of Sophie. In London in 1907, when she played Polly Love in a revival of The Christian at the Lyceum Theatre. She appeared in 1908 in the London musical Kitty Grey. This was followed the next autumn by an appearance in the long-running American version of The Dollar Princess (1909). Valli had the role of Alice Cowder. In 1916, she participated in George M. Cohan’s The Cohan Revue. Her last New York City performance was in Miss Millions in 1919 at the Punch and Judy Theatre.  Valli made four films in the years 1915 and 1916. One of these is The Turmoil, an adaptation of a Booth Tarkington novel. Valli’s character is Mary Vertrees, a lady with an aristocratic bearing. Her other screen credits are for appearances as Mary Page in The High Road (1915), Beth Coventry in The Woman Pays (1915), Marian Delmar in Her Debt of Honor (1916). In 1917, she married Louis Dreyfus, head of the music publishing house Harms, Day and Hunter and later a theatrical producer.  Valli died at her home in Hampstead, London, in 1927 at the age of 45, survived by her husband.