James Murray was born on January 21, 1721, at Ballencrieff in East Lothian, Scotland. He was a younger son of Alexander Murray, 4th Lord Elibank, and Elizabeth Stirling. The Murrays were a well-connected but not exceptionally wealthy Scottish noble family, and several sons pursued military, naval, or imperial careers. James’s position as a younger son made professional service a natural path. His family also included strong and sometimes conflicting political loyalties, a common feature of Scottish elite life after the Union of 1707.

Murray entered the army in 1736 as an ensign in the 3rd Scots Guards. He transferred among regiments as he sought promotion and active employment. During the War of Jenkins’ Ear he served in the unsuccessful 1740 expedition against Cartagena de Indias, where disease killed far more men than combat. Surviving that campaign gave him early experience of amphibious operations, tropical illness, and the consequences of defective planning and supply.

He later served in Flanders during the War of the Austrian Succession and was wounded at Ostend in 1745. Murray also participated in the 1746 expedition against Lorient on the French coast. Although the operation did not capture its objective, it familiarized him with joint army-navy expeditions and assaults against fortified ports. He gradually developed a reputation as a brave, energetic, and sometimes sharp-tempered officer.

Promotion was not automatic. Murray relied on family advocacy, professional persistence, and the purchase or exchange of commissions customary in the eighteenth-century army. By 1751 he was lieutenant colonel of the 15th Regiment of Foot. His years of service had taken him from court regiments to disastrous colonial expeditions and European battlefields. When the regiment was sent to North America during the Seven Years’ War, Murray arrived with substantial experience in siegecraft, amphibious campaigning, discipline, and the survival of armies operating far from their normal supply systems.