Transferred to Spain in 1808, Trelliard led a dragoon division and participated in the third invasion of Portugal in 1810-1811. He commanded his dragoons at Majadahonda in 1812 and at Vitoria and the Pyrenees in 1813. His division was redeployed to eastern France for Emperor Napoleon's final futile campaign in 1814. After rallying to Napoleon during the Hundred Days, the Bourbons dismissed him from the army. Trelliard is one of the names inscribed under the Arc de Triomphe.