Hely-Hutchinson supported the continuation of the Napoleonic Wars. In 1806 he accompanied Lord Hutchinson on a diplomatic mission to St. Petersburg and Berlin. In 1807 he took part in the Polish campaign, fighting in the Russian ranks. He was wounded in the battle of Eylau, and was also present at the Battle of Friedland. After the Peace of Tilsit he visited Moscow, and on his return to England in the beginning of 1809 he opposed the ministry for their mismanagement of the war, and particularly for the Convention of Cintra.