A half-length, head-and-shoulders portrait facing to the right. The sitter wears a brown suit, waistcoat, white shirt and dark tie, and looks forwards to meet the gaze of the viewer.

Born in Ireland, Shackleton was educated at Dulwich College, London, before becoming a merchant seaman in sail and steam and then an explorer who three times attempted to reach the South Pole. In 1901 he sailed as a member of Captain Robert Falcon Scott's first expedition to Antarctica, in the 'Discovery', and was one of Scott's party who reached 'furthest south' before being forced to turn back. In 1907 commanding his own expedition in 'Nimrod', he again attempted to reach the South Pole, coming within 179 km of his goal, a new record, for which he was knighted. In 1914, after both Amundsen and Scott had reached the Pole, he sailed in the 'Endurance' to try and cross Antarctica from the Weddell Sea to the Ross Sea, via the Pole. Instead 'Endurance' was trapped before reaching land in the Weddell Sea ice and eventually crushed, marooning Shackleton and his men on the northward drifting pack. From this they finally made a dangerous escape in boats to Elephant Island, followed by Shackleton's epic 800-mile voyage in the 'James Caird', with five companions, to seek help from South Georgia. In 1916 he rescued all his men from Elephant Island and then the survivors of his second party in the Ross Sea.

In 1921, after army service in the later part of the First World War, Shackleton undertook one more Antarctic trip in the 'Quest', an expedition largely supported by a wealthy fellow pupil at Dulwich, John Quiller Rowett. However, on 15 January 1922, on the night of his arrival at Grytviken, South Georgia, Shackleton died suddenly of a heart attack, aged 47. His exertions to finance his expeditions and the immense strain of the journeys themselves wore out his strength. There is also little doubt that he had a longstanding heart condition, which he had consistently refused to have investigated.

This portrait was probably painted from life before Shackleton set off on his final voyage and was purchased from the sale of the artist's studio collection at Bonham's in 1974. The Scott Polar Research Institute at Cambridge has a sketch for it. The National Portrait Gallery has a smaller version (NPG2608, 610 x 508 mm/ 24 x 20 ins) also dated 1921 and showing the sitter dressed the same way, but turned to face the viewer.