This portrait was one of two commissioned by William IV (OM 1086-7, 401453 and 405141) and exhibited at the Royal Academy in 1836, where it was stated explicitly that they were intended for the Waterloo Chamber. Both sitters were British heroes of that battle, and reflect the move at this time to make the Chamber live up to its name, rather than being (as originally intended) more about the international diplomatic activity following the defeat of Napoleon.

Shee was an Irish writer and painter whose first contact with royalty was a commission in 1800 to paint the Duke of Clarence (later William IV). His moment came in 1830 when William IV succeeded his brother and when he succeeded Lawrence as President of the Royal Academy and was knighted in the same year. All the original works of Shee in the collection were commissioned or acquired by William IV. Shee did also paint Queen Victoria in 1842 (Royal Academy).

The subject of this portrait is Sir Thomas Picton, the most senior British officer to have died at the Battle of Waterloo. Picton began his military career in Gibraltar, where he learnt Spanish. This would later prove useful when he was appointed commandant and military governor general of Trinidad, then under Spanish law. Picton's punitive administration of Trinidad and his subjects' enforced adherence to strict penal codes were the subject of contemporary controversy in Britain and the West Indies. He was brought to trial in London in 1806, accused of carrying out torturous practices in jails under his jurisdiction. He was later partially exonerated, on the grounds that while he had committed illegal acts not befitting his role as military governor, the right to torture prisoners was recognised under the Spanish laws still enforced at the time.  

In this portrait, Picton appears in the uniform of a Lieutenant-General, wearing the ribbon and star of the Order of the Bath and the badge of the Order of the Tower and Sword of Portugal; he rests his right hand on his sword.