Joining the newly raised 83rd Foot, Carr was posted to the West Indies where he saw action in the Second Maroon War in Jamaica and in Santo Domingo and was wounded, requiring long convalescence. In 1802 the regiment was recalled to the United Kingdom and the 2nd Battalion was not thrown into action again until 1809, when it was sent to Lisbon to counter the French invasion of Portugal. After fighting at the Second Battle of Porto and at the Battle of Talavera, in 1810 the 83rd were engaged at the Battle of Bussaco. Its commanding officer was then promoted to lead a Portuguese brigade and for the rest of the war the 2nd Battalion was led by the then Major Carr.