At the French invasion of 1808, Cartaojal rallied to the insurgents and placed himself at the orders of General Cuesta in Valladolid, who dispatched him to Seville to give an account to the Juntas of the Spanish defeat at Medina de Rioseco. Promoted Lieutenant General upon Napoleon's destruction of the Spanish armies, Cartaojal took to the field with a reconstituted Army of the Centre but was crushed by General Sebastiani at the Battle of Ciudad-Real and sacked for incompetence.