In the present portrait Admiral Keppel's stance and expression exude defiance, his left arm propped upon his hip while his right hand grasps the hilt of his sword. Framed against the sea and the setting sun, Keppel stands with his ample figure anchored firmly on the rocky promontory. Keppel paid Reynolds one hundred guineas for the picture in 1786, by which time he may already have presented it to Thomas Erskine (1750-1823), the lawyer who had masterminded Keppel's defence at his court martial several years earlier.
Augustus Keppel (1725-86), 1st Viscount Keppel, came from a distinguished aristocratic family. He was the second son of William Anne, 2nd Earl of Albemarle (1702-54) and Lady Anne Lennox, daughter of Charles, 1st Duke of Richmond (1672-1723). His grandfather was Arnold Joost van Keppel, 1st Earl of Albemarle (1669-1718), an intimate friend of William III, and one of the principal architects of the Glorious Revolution of 1688. Keppel gained a commission in the navy at the age of ten, when he sailed for Africa. Five years later he circumnavigated the globe with Lord George Anson (1697-1762). In 1749, by now a vastly experienced seaman, he met Reynolds, to whom he offered a passage to Italy, and whose close friend he became. Reynolds painted Keppel's portrait on many occasions, among the first, and the most celebrated, being a full-length of Keppel striding Apollo-like across a storm-tossed shoreline (Greenwich, National Maritime Museum).
During the 1750s and 60s Keppel remained on active service, although he was also increasingly involved in politics on the side of the Rockinghamite Whig Opposition, serving as Member of Parliament P for Windsor. In 1770 he was promoted to the rank of Vice-Admiral. In November 1776, despite his close ties to the Opposition, Keppel was appointed by the King to take command of the Channel fleet against the French and, in January 1778, he was promoted to the rank of Admiral. Later that year he was accused of deliberately failing to engage the enemy in an indecisive skirmish off the French coast. For the second time in his career, Keppel was brought before a court martial at Plymouth, where a guilty verdict could have resulted in the death penalty. He was acquitted on 11 February 1779, confirming his status as the hero of the Whig cause and scourge of the Court Party. Reynolds was among those who sent their immediate congratulations.
On his acquittal Keppel commissioned from Reynolds a new portrait of himself, in his flag-officer's undress uniform. This portrait, which is not to be confused with the present picture, was replicated several times by the artist, versions being presented to his lawyers, John Lee (1733-93) (National Maritime Museum, London), and John Dunning (1731-83) (National Portrait Gallery, London), and to Edmund Burke (1729-1797) (private collection). A replica also appears to have been made for Thomas Erskine, who, as it has been noted, also owned the present portrait.
David Mannings and Martin Postle, Sir Joshua Reynolds. A Complete Catalogue of his Paintings, 2 vols., New Haven and London 2000, vol.1, p.1048, vol.2, p.522, fig.1367, and colour plate 92