He was the son of the Reverend and Mrs. William Samuel Davenport.
He attended Union Academy (Union Endicott High school) and graduated from the University of Pennsylvania Dental School in 1890. He then moved to London, and later set up a dental practise in Paris. His brother Dr Isaac Burnet Davenport was also a dentist who lived in Paris.
W. S. Davenport was Whistler's dentist in Paris. Whistler thought very highly of him and would send both models and servants to him when they had toothache. For example, in 1896 he sent his model Lillie Pennington for treatment (GUW #09072) and on another occasion his maidservant (#10572). Whistler's sister-in-law Rosalind Birnie Philip consulted Davenport's brother when in Paris in the late 1890s. Whistler told J. J. Cowan, 'their operating was just like the flutter of a butterfly in his mouth'.
Whistler began to paint a portrait of Davenport's brother in 1894 but this was abandoned and another begun in 1895, Portrait of Dr Isaac Burnet Davenport y426. I. B. Davenport sat on and off for this painting until 1902/1903. After Whistler's death, the portrait was varnished and sent to the sitter. It was exhibited at the Whistler memorial exhibition in Paris in 1905.
Whistler attended séances run by the Davenport brothers in Paris.
He painted landscapes and architectural subjects, and painted some pictures in Paris. He exhibited at the Paris Salon of the Société Nationale des Beaux-Arts, of which he was an associate member, and later at the Salon des Tuileries. He was made an Officier of the Légion d'Honneur in France.
Young, Andrew McLaren, Margaret F. MacDonald, Robin Spencer, and Hamish Miles, The Paintings of James McNeill Whistler, New Haven and London, 1980 ; MacDonald, Margaret F., James McNeill Whistler. Drawings, Pastels and Watercolours. A Catalogue Raisonné, New Haven and London, 1995 .