A half-length portrait to right wearing a dark dun-coloured coat and a grey full-bottomed wig. He holds his palette and brushes in his left hand. The background is a lighter colour.

Thornhill was a portrait and history painter, the most successful painter of decorative interiors of the English school, and the first native British artist to be knighted (1720). His masterpiece is the Painted Hall at Greenwich, which he was commissioned to do in 1707. He completed the ceiling in 1712 and the remainder by 1726.

Laroon was an English painter and draughtsman of French origin. His father was Marcellus Laroon the elder (d. 1702), a French portrait painter and copyist who came to England from The Hague. In 1707 the son enlisted in the army, participating in campaigns in Flanders, Spain and Scotland. During a break from military life, 1712-15, he joined the Rose and Crown Club in London and worked in Kneller's Academy, where Thornhill became a director in 1716. It is probably during this period that the portrait was painted, when Thornhill was working on a variety of decorative schemes in Dorset, Northamptonshire, Surrey, in Pall Mall and the cupola of St Paul's Cathedral in London, at Deptford and at Hampton Court. Laroon did not begin to concentrate fully on art until his retirement from the army in 1732. He appears to have worked for pleasure rather than profit. Besides a large number of drawings he produced pastoral fancy pictures in the French mode, as well as scenes from the theatre. His drawings, dating primarily from the 1720s and 1730s, show a rococo influence and demonstrate tapestry-like compositions. He experimented with genre scenes in the Dutch and Flemish manner and created conversation pieces, although none of the figures is identifiable. In the late 1750s he settled in Oxford.

This painting - then thought to be a self-portrait by Thornhill - was presented as an addition to the Greenwich Hospital Collection in 1961 by a London dealer, the late Monty Bernard of Ryder Street, St James's. The reattribution to Laroon was later suggested to the NMM by his King Street neighbour, William Drummond.