A half-length portrait slightly to right in a blue coat edged with gold lace, and with a gold-laced mariner's cuffs and a red waistcoat, also laced, and a grey tie-wig. Osborn's right hand rests on a box compass, while his left hand lacks cuffs and appears unfinished as does the background of sea, which has no shipping. The portrait was probably painted on board his ship 'Princess Caroline', 80 guns, in Hyères Bay, when the fleet was blockading Toulon. At the ensuing but indecisive Battle of Toulon in 1744, Osborn commanded the 'Princess Caroline' in the main division, and nobly supported Captain William Rowley. The fact that the fleet left after the action probably explains why Arnulphy was unable to finish this picture. In 1758, commqnding a squadron blockading Cartagena, he intercepted the French 80-gun 'Foudroyant' and the 'Oriflamme' , 50, dispatching ships in pursuit which captured the former and destroyed the latter. Shortly afterwards he suffered a stroke which foced him to give up command, though he rose to become Admiral of the White and was appointed Vice-Admiral of England in 1763. John Charnock's 'Biographia Navalis' (1797) gives an unflattering portrait of Osborn as a rather dour character, not supported by other sources. He was perhaps idiosyncratic but reliable, humane, liked by his followers and described by Augustus Hervey as a 'worthy good man'.

The French-born artist worked exclusively as a portrait painter and spent most of his working life in Provence. This is one of a group of portraits he painted of English naval officers while Mathews' fleet was blockading Toulon.