This retrospective, highly romanticized portrait was painted some 170 years after Blake's death. It shows him full-length to the left, wearing a breast-plate and leather coat with a red sash and cloak, breeches, and stockings. He wears red ribbons on his shoes. He stands on the deck of a ship and, holding a sword in his gloved right hand, he points it over the gunwale and out to sea. He holds his other glove in his left hand and stands in front of a cannon, while to the right in the foreground the sheath of his sword lies on the deck.

Blake was one of the first to take up arms against King Charles I and as commander of the navy of Oliver Cromwell's Commonwealth became one of the most renowned seamen in English history. In 1640 he was elected to the Short Parliament and his staunch Puritanism led him to join the Parliamentary cause against King Charles I at the outbreak of the Civil War in 1642. He soon won fame as a general by brilliantly defending Lyme, Dorset, in 1644 and by holding Taunton, Somerset, from its besiegers for more than a year 1644-45. He was appointed General-at-Sea in 1649 and led the English fleet against the Dutch, 1652-54, and against the Spanish 1656-57. His articles of war and fighting instructions represented fundamental reforms, which helped to lay the foundations of England's maritime supremacy. The artist has played on 19th-century interest in the heroic to create this portrait, which was commissioned by Sir Robert Preston Bt., one of the Directors of Greenwich Hospital, for presentation to the Naval Gallery there in 1829. It was reputed to be based on a contemporary miniature of Blake.