Portrait d'Hélène Keller depicts the daughter-in-law of a close friend of Van Rysselberghe's, the celebrated radiologist and 19th century collector, Dr. Jean Keller. The work, known alternatively as La dame blanche and commonly held at the time to be a portrait of the artist's wife, was exhibited to great acclaim at the Paris Salon d'Automne of 1907, where it was hailed as one of the highlights of the show. A daguerreotype of Hélène Keller exists from this time, which shows her without the dog, in the same relaxed pose as in Van Rysselberghe's portrait.

Van Rysselberghe's pointillist technique, based on the optical lessons of Georges Seurat, of juxtaposing small dots of complementary color designed to fuse in the spectator's eye, was already giving way at this time to a freer, less rigorous style which made use of looser and more varied brushstrokes. Van Rysselberghe was one of the few artists to employ a divisionist technique in his portraiture and used it to great effect to render the atmosphere of his painting. The present work displays a scintillating use of color in the white of the sitter's dress and in the divan, while accentuating the overall opulence of her surroundings.