Carmichael is noted for recognising the value and usefulness of incorporating native Caribbean troops into the British Army. In 1797, he wrote that they were not only critical militarily, but their strength and stamina had been proven by their having to carry British soldiers through the heat and over the rocks at the Battle of Grenada. He campaigned for the right of slave soldiers to give evidence at Military tribunals. White and black soldiers alike were brutally flogged for violating military rules, but Carmichael found a more humane method to be equally as effective: During his eleven years as Lieutenant-Colonel of the 2nd West India Regiment, Carmichael instead demoted native offenders to a position resembling that of a common field slave – deprived of weapons and appointments and employed only on fatigue duties.