This portrait has traditionally been attributed to Thomas Hudson, however, it appears closer to the work of Hudson's contemporary George Knapton. Stylistically it can be compared with Knapton's portrait of Richard Boyle, 3rd Earl of Burlington, whose daughter and heir, Catherine, married the 3rd Duke of Devonshire's eldest son and heir, William, later 4th Duke of Devonshire, in 1748 (Devonshire collections, Chatsworth; for which see J. Kerslake, National Portrait Gallery, Early Georgian Portraits, London, 1977, I, p. 30, II, pl. 89.).
William, 3rd Duke of Devonshire (1698-1755), served as Lord Lieutenant of Ireland from 1737 to 1744 and was a Member of Parliament from 1721 until his father's death in 1729 when he succeeded to the Dukedom. He was made a Knight of the order of the Garter by Queen Anne in 1733. The Duke was also portrayed by Sir Joshua Reynolds in a three-quarter-length portrait (Devonshire Collections, Chatsworth; see D. Mannings, Sir Joshua Reynolds, A Complete Catalogue of his Paintings, New Haven and London, 2000, I, no. 333, II, fig. 72).