James Stuart commenced his career of brilliant and honorable service, as ensign in the sixty-fourth regiment, in October, 1761; in 1764 he was promoted to a lieutenancy, and in 1768 he accompanied the regiment to North America, where he was advanced to captain of the grenadier company in 1770. He was stationed at Boston when hostilities commenced between Great Britain and the colonies in North America. He shared in the severe duties at Boston during the winter of 1775-6, when that town was blockaded on the land side by the Americans, and subsequently proceeded to Halifax, from whence he sailed with the expedition towards New York, and was employed, under General Sir William Howe, in the reduction of Long Island, in August, 1776, also in the movements by which possession was gained of New York, and the Americans forced from their positions at White Plains, which was followed by the capture of Fort Washington and Fort Lee. In the summer of 1777 he was engaged in operations in the Jerseys, and afterwards in the expedition to Pennsylvania; he was engaged at the battle of Brandywine, and in repulsing the attack of the Americans on the position at Germantown. In the winter he was selected, as an officer of ability and experience, for the commission of major in the regiment of Highlanders, raised by the Earl of Seaforth, now the SEVENTY-SECOND, or Duke of Albany’s Own Highlanders, to which he was appointed by commission dated the 18th of December, 1777; but he did not arrive from America until August, 1778. He accompanied his regiment to the East Indies in 1781, with the local rank of lieut.-colonel in that country, and on the 2nd of June, 1782, he was at the action with the forces of Hyder Ali near Arnee, under Lieut.-General Sir Eyre Coote. He commanded his regiment, in which he had been appointed lieut.-colonel in February, 1782, under Major-General Stuart, in the action near Cudalore, on the 13th of June, 1783, and was commended in the general’s public despatch, and in orders. He served at the siege of Cudalore; and subsequently penetrated into the Mysore under Colonel Fullerton, and was at the capture of the fortresses of Palacatcherry and Coimbetore. In 1788 he commanded a detachment sent against the refractory Rajah of the little Murwar country, when he engaged his opponents at Kallengoody, and captured Caliacoil, the capital. When Tippoo Sultan attacked the Rajah of Travancore, a British ally, Lieut.-Colonel Stuart commanded the left wing of the army assembled on Trichinopoly plain under Major-General Medows, and penetrated the Mysore. After the capture of Caroor, Daraporum, and Coimbetore, he was detached on the 23rd of July, 1790, against Palacatcherry, but his progress was impeded by heavy rains and mountain torrents, and his force was too weak for the reduction of the fortress; he therefore returned to Coimbetore. He was again detached, on the 2nd of August, against the fortress of Dindigal, which he took after a short siege.