On 18 June 1809, von Löw was promoted to Brigadier General and placed in command of the brigade. The previous commander, Brigadier General von Drieburg, had returned to Britain to recover his health, and von Löw was the senior Colonel in the Legion. His first chance to lead them in combat was at the battle of Talavera, where they were badly mauled following an ill-timed charge across the Portina stream. In August, following the death of General Langwerth, he was given command of a new KGL brigade, the largest in Wellington's army. He led this force at Bussaco, Fuentes de Oñoro, Ciudad Rodrigo, Salamanca and Burgos.