Sir Charles Munro entered the British Army as Ensign in the 45th (Nottinghamshire) Regiment of Foot, and served with much distinction, under the Arthur Wellesley, 1st Duke of Wellington - who in the General Orders of Madrid described Sir Charles Munro as "one of the bravest officers in the British Army", in the Peninsular Campaign, from 1810 to the conclusion of the war in 1815. He was badly wounded at the storming of Badajoz. As an acknowledgment of his distinguished services he was awarded a medal with seven clasps: for the Siege of Ciudad Rodrigo (1812) (18 January 1812), Battle of Badajoz (6 April 1812), Battle of Salamanca (22 July 1812), Battle of Nive (13 December 1813), Battle of Orthez (17 February 1814), and Battle of Toulouse (10 April 1814).