Brace entered the navy in 1781, became Lieutenant in 1792, Commander in 1797 and Captain in 1800. In 1803 he became flag-captain to Admiral Cornwallis. He held commands at home and later in the Mediterranean until the end of the war with France. In 1816 he took command of the ‘Impregnable’ in Lord Exmouth’s squadron at the bombardment of Algiers where the ship was badly damaged because she failed to anchor in her proper station. He died while Commander-in-Chief at the Nore.

He is wearing captain’s full dress uniform of the 1812–25 pattern, with the CB (Companion of the Bath), the Order of Wilhelm of the Netherlands, St Maurice and St Lazarus of Sardinia, and Charles II of Spain. He faces the sitter and wears a cloak with a red lining over his uniform and a fur collar. Painted in 1816–17, a later inscription upper right gives his name, his rank as rear-admiral, dates and position at the Nore. In the upper left corner are his arms as knight, probably also a later addition.

It is not known on what evidence the attribution to Thomas Stewardson is based.