A posthumous portrait based on an unidentified source showing him three-quarter-length standing slightly to the right, wearing a buff coat lined with red over a red waistcoat, with a loose white stock. His hair, although painted as his own, long, powdered and dishevelled by wind, is more probably a full-bottomed wig. His left hand rests on the fluke of an anchor, his right gestures towards the viewer.

In the right background is a stormy seascape with three ships in distress, the most prominent being his flagship, the 'Mary' (in which he was drowned in 1703) flying a blue ensign and his rear-admiral's blue flag at the mizzen. This element is in the manner of van de Velde and possibly by his studio (cf. BHC3101), though Dahl seems to have done some of his own marine backgrounds.

Beaumont was the fifth son among twenty-one children of Sir Henry Beaumont, Bt (1638–1689), of Stoughton Grange and Coleorton, Leicestershire. Distantly related to the Duke of Buckingham, he entered the Navy as a king's-letter boy in 1684 and was appointed lieutenant of the 'Portsmouth' in October 1688. On 21 April 1689 he was promoted captain of the 'Centurion', which was lost by storm in Plymouth Sound on 25 December, though he was not blamed. Because of this and the patronage of Admiral Arthur Herbert, Earl of Torrington, he was quickly appointed to the 'Foresight', then the 'Dreadnought' in December 1690, and early in 1692 to the 'Rupert', which he commanded at the Battle of Barfleur in May. In 1694 he commanded the 'Canterbury' in the Mediterranean.

In 1696, when commanding the 'Mountagu' in the channel fleet, he was detached as commodore of an inshore squadron and destroyed some small craft in Camaret Bay. He was subsequently in the 'Plymouth', 'Neptune' and 'Duke' while in command of the squadron off 'Dunkirk' during the remainder of 1696 and until the Peace of Ryswick (1697). In November 1698 he moved to the 'Resolution' and in 1699 was senior officer at Spithead, until the ship paid off in late August, though he recommissioned her a little later and remained in her for the next two years, commanding in the Downs for much of the time and unsuccessfully seeking promotion to flag rank. In June 1702 he moved to the 'Tilbury' and continued to command in the Downs, at the Nore, and off Dunkirk. On 1 March 1703 he was promoted rear-admiral, hoisting his flag in the 'Mary', then fitting out at Woolwich, but remained on the same station. That summer he cruised in the North Sea and off Dunkirk, and convoyed the Baltic trade, returning to anchor in the Downs on 19 October. He was still there on 27 November when the Great Storm of 1703 drove his ship, along with the 'Stirling Castle' and the 'Northumberland' on to the Goodwin Sands. The 'Mary' was lost with all hands.

Beaumont, only 34 when he died, had risen rapidly thanks to his connections rather than notably distinguished service: his posthumous fame is in having been the most senior officer lost in the Great Storm, which caused some 2000 naval deaths, mainly in the Goodwin wrecks, and about 6000 others afloat and ashore. His mother petitioned Queen Anne for a pension in 1704, claiming that he had been the sole support for his two younger brothers and six sisters, three other brothers having already died in public service, two in the navy (William, of a fever in the West Indies in 1697; Charles, blown up in the 'Carlisle' in 1700). The outcome was that the six daughters were each granted £50 a year.

The painting is one of the Kneller and Dahl 'admirals' set commissioned by Prince George of Denmark (d. 1708), Lord High Admiral for his wife Queen Anne, which George IV presented to Greenwich Hospital in 1824.