Ralph Darling enlisted at the age of fourteen as a private in his father's regiment, and served in the ranks for at least two years on garrison duty in the West Indies. Eventually, as an "act of charity" to the family, young Ralph was granted an officer's commission as an ensign on 15 May 1793, without having to make the usual payment. The new officer soon found opportunities to show his ability, alternating front-line activity and high-level administrative duties, and in August 1796 he was appointed as military secretary to Sir Ralph Abercromby, the British commander-in-chief in the West Indies. By the time he returned to Great Britain in 1802, still aged only twenty-nine, the sergeant's son and one-time private soldier was a highly respected lieutenant-colonel.