Blakeney joined Sir Arthur Wellesley in Spain in June 1810 and commanded the 2nd Battalion of his regiment during the Battle of Bussaco in September 1810 and the Battle of Albuera (where he was severely wounded in the thigh) in May 1811. He commanded both battalions of his regiment at the Combat of Aldea da Ponte in September 1811, at the Siege of Ciudad Rodrigo in January 1812 and at the Siege of Badajoz (where he was severely wounded through the arm in the assault) in April 1812. He also commanded at the Battle of Vitoria in June 1813, at the Combat of Pampelona in June 1813 and at the Battle of the Pyrenees in July 1813 as well as the Battle of Nivelle in November 1813. Promoted to colonel on 4 June 1814 and appointed a Knight Commander of the Order of the Bath on 2 January 1815, he fought at the Battle of New Orleans in January 1815 during the War of 1812. Although he did not take part in the Hundred Days, he joined the Duke of Wellington as he marched into Paris in 1815 and served with the Army of Occupation in France until 1819.