1786, Ralph Darling, at the age of 14, entered the army as a private in his father's regiment, and served for two years on garrison duty at Grenada. From 1788 until 1792 it appears he became a customs officer on the island and achieved a high level of education and familiarity with colonial administration.

With the outbreak of war against France in 1793, Ralph was granted an officer's commission as an ensign